Behrend v. Comcast Corp.

PRECEDENTIAL

UNITED STATES COURT OF APPEALS
FOR THE THIRD CIRCUIT
__________

No. 10-2865
__________

CAROLINE BEHREND; STANFORD GLABERSON;
JOAN EVANCHUK-KIND; ERIC BRISLAWN

v.

COMCAST CORPORATION; COMCAST HOLDINGS
CORPORATION; COMCAST CABLE
COMMUNICATIONS, INC.; COMAST
CABLECOMMUNICATIONS HOLDINGS, INC.;
COMCAST CABLE HOLDINGS, LLC,

Appellants

__________

On Appeal from the United States District Court
for the Eastern District of Pennsylvania
(D.C. No. 2-03-cv-06604)
District Judge: Honorable John R. Padova
__________

Argued on January 11, 2011
Before: FISHER, JORDAN and *ALDISERT, Circuit Judges.

(Filed: August 23, 2011)

Darryl J. May
BALLARD SPAHR LLP
1735 Market Street, 51st Floor
Philadelphia, PA 19103-75999

Michael S. Shuster [ARGUED]
Sheron Korpus
KASOWITZ, BENSON, TORRES & FRIEDMAN LLP
1633 Broadway, 21st Floor
New York, NY 10019

Attorneys for Appellants

Samuel D. Heins
Vincent J. Esades
David R. Woodward
Jessica N. Servais
HEINS MILLS & OLSON, P.L.C.
310 Clifton Avenue
Minneapolis, Minnesota 55403

Anthony J. Bolognese

*
Subsequent to oral argument, Judge Aldisert replaced Judge
Ambro on the panel. The case was not reargued because the
replacement Judge exercised his right to decide the case on
the basis of the brief, the record and a transcript of the
original oral argument.

2
Joshua H. Grabar
BOLOGNESE & ASSOCIATES, LLC
Two Penn Center Plaza
1500 JFK Boulevard, Suite 320
Philadelphia, PA 19102

Barry C. Barnett [ARGUED]
Daniel H. Charest
Stephen L. Shackelford, Jr.
SUSMAN GODFREY L.L.P.
901 Main Street, Suite 5100
Dallas, Texas 75202-3775

Joseph Goldberg
FREEDMAN BOYD HOLLANDER GOLDBERG & IVES
20 First Plaza, Suite 700
Albuquerque, NM 87102

Attorneys for Appellees

__________

OPINION OF THE COURT
__________

ALDISERT, Circuit Judge.

In 2008 this Court handed down the seminal case of In
re Hydrogen Peroxide Antitrust Litigation, 552 F.3d 305 (3d
Cir. 2008), which outlines the standards a district court should
apply in deciding whether to certify a class. This appeal by
Comcast requires us to decide if the District Court for the

3
Eastern District of Pennsylvania properly satisfied
Hydrogen‘s directions in determining that questions of fact or
law common to class members predominate sufficiently to
satisfy Rule 23(b)(3) of the Federal Rules of Civil Procedure.
Appellants contend that the District Court exceeded a proper
exercise of discretion and that its findings of fact were clearly
erroneous. For the reasons that follow, we hold that the Court
did not exceed its permissible discretion in determining that
Plaintiffs established by a preponderance of evidence that
they would be able to prove through common evidence (1)
class-wide antitrust impact (higher cost on non-basic cable
programming), and (2) a common methodology to quantify
damages on a class-wide basis. Accordingly, we will affirm.

I.

A.

―For the rational study of the law the black-
letter man may be the man of the present, but
the man of the future is the man of statistics and
the master of economics.‖

Oliver Wendell Holmes, Jr., The Path of the
Law, 10 Harv. L. Rev. 457, 469 (1897).

Beginning in 1998, Defendants Comcast Corporation,
Comcast Holdings Corporation, Comcast Cable
Communications, Inc., Comcast Cable Communications
Holdings, Inc., and Comcast Cable Holdings, LLC
(collectively ―Comcast‖) engaged in a series of transactions
that increased Comcast‘s share of the multichannel video
programming distribution services offered in the Philadelphia

4
Designated Market Area (―Philadelphia DMA‖).1 Comcast
contracted with competing cable providers to either acquire
them or to ―swap‖ cable systems it owned in areas outside the
Philadelphia DMA for cable systems within the Philadelphia
DMA. These transactions form the ―Cable System
Transactions,‖ involving the ―Transaction parties.‖2 As a

1
―A DMA is a specific media research area that is used by
Nielsen Media Research to identify television stations whose
broadcast signals reach a specific area and attract the most
viewers. DMA boundaries are widely accepted and used by
all types of companies to target and keep track of
advertising.‖ Steak n Shake Co. v. Burger King Corp., 323 F.
Supp. 2d 983, 986 n.2 (E.D. Mo. 2004).
2
The District Court set forth the Cable System Transactions:
 The April 1998 acquisition of Marcus Cable and its
27,000 cable subscribers located in Harrington,
Delaware, which is part of the Philadelphia DMA.
 The June 1999 acquisition of Greater Philadelphia
Cablevision, Inc., a subsidiary of Greater Media, Inc.,
and its 79,000 cable subscribers located in
Philadelphia.
 The January 2000 acquisition of Lenfest
Communications, Inc. and more than 1.1 million cable
subscribers located in Berks, Bucks, Chester,
Delaware, and Montgomery counties in Pennsylvania,
and New Castle County in Delaware.
 The January 2000 acquisition of Lenfest‘s ownership
interests in Garden State Cablevision L.P. and its
212,000 customers located in Atlantic, Burlington,
Camden, Cape May, Cumberland, Gloucester, Mercer,
and Salem counties in New Jersey, which is part of the
Philadelphia DMA.

5
result of the Cable System Transactions, Comcast‘s share of
subscribers in the Philadelphia DMA allegedly increased
from 23.9 percent in 1998 to 77.8 percent by 2002, settling at
69.5 percent in 2007. See Behrend v. Comcast Corp., 264

 The December 2000 swap agreement with AT & T,
wherein Comcast obtained cable systems and
approximately 770,000 subscribers, including
subscribers located in Eastern Pennsylvania (Berks and
Bucks counties) and New Jersey. In exchange, AT & T
obtained cable systems and approximately 700,000
Comcast subscribers located in Chicago and elsewhere
around the country.
 The January 2001 swap agreement with Adelphia
Communications Corp., wherein Comcast obtained
cable systems and approximately 464,000 subscribers
located primarily in the Philadelphia area and adjacent
New Jersey areas. In exchange, Adelphia received
Comcast‘s cable systems and subscribers located in
Palm Beach, Florida and Los Angeles, California.
 The April 2001 swap agreement with AT & T, wherein
Comcast obtained cable systems and approximately
595,000 subscribers, including subscribers located in
Pennsylvania and New Jersey.
 The August 2006 swap agreement with Time Warner
in connection with the Adelphia bankruptcy, wherein
Comcast obtained cable systems and approximately
41,000 subscribers in the Philadelphia DMA.
 The August 2007 acquisition of Patriot Media and its
81,000 cable subscribers located in New Jersey, within
the Philadelphia DMA.
Behrend v. Comcast Corp., 264 F.R.D. 150, 156 n.8 (E.D. Pa.
2010).

6
F.R.D. 150, 160 (E.D. Pa. 2010) (setting forth Plaintiffs‘
expert‘s calculations as to Comcast‘s market share).

Plaintiffs, six non-basic cable television programming
services customers of Comcast, brought a class action
antitrust suit against Comcast in 2003. They alleged
violations of section 1 of the Sherman Act, 15 U.S.C. § 1, for
―imposing horizontal territory, market and customer
allocations by conspiring with and entering into and
implementing unlawful swap agreements, arrangements or
devices,‖ and section 2 of the Sherman Act, 15 U.S.C. § 2, on
theories of monopolization and attempted monopolization.3
App. 00232-243 (Third Am. Compl.). The Complaint alleged
anticompetitive conduct in the Philadelphia area and the
Chicago area. As only the alleged conduct in Philadelphia is
before us, we focus on the nature of the class and the
allegations in Philadelphia.

The proposed class included: ―All cable television
customers who subscribe or subscribed at any time since
December 1, 1999, to the present to video programming
services (other than solely to basic cable services) from
Comcast, or any of its subsidiaries or affiliates in Comcast‘s

3
Section 1 of the Sherman Act states: ―Every contract,
combination in the form of trust or otherwise, or conspiracy,
in restraint of trade or commerce among the several States, or
with foreign nations, is declared to be illegal.‖ 15 U.S.C. § 1.
Section 2 states: ―Every person who shall monopolize, or
attempt to monopolize, or combine or conspire with any other
person or persons, to monopolize any part of the trade or
commerce among the several States, or with foreign nations,
shall be deemed guilty of a felony . . . .‖ Id. § 2.

7
Philadelphia cluster.‖ App. 00217; see id. (excluding from the
class ―governmental entities, Defendants, Defendants‘
subsidiaries and affiliates and this Court‖). The Philadelphia
cluster is composed ―of the areas covered by Comcast‘s cable
franchises, or any of its subsidiaries or affiliates, located in
the following counties: Berks, Bucks, Chester, Delaware,
Montgomery and Philadelphia, Pennsylvania; Kent and New
Castle, Delaware; and Atlantic, Burlington, Camden, Cape
May, Cumberland, Gloucester, Mercer and Salem, New
Jersey.‖ See Behrend, 264 F.R.D. at 191.4

The Complaint alleged that Comcast had perpetrated
an anticompetitive ―clustering scheme.‖ To clarify its
contentions we pause to define two key terms. ―Clustering‖
refers to a ―strategy whereby cable [Multi-System Operators
(―MSOs‖)] concentrate their operations in regional
geographic areas by acquiring cable systems in regions where
the MSO already has a significant presence, while giving up
other holdings scattered across the country. This strategy is
accomplished through purchases and sales of cable systems,
or by system ‗swapping‘ among MSOs.‖ Implementation of
the Cable Television Consumer Prot. & Competition Act of
1992, 22 F.C.C. Rcd. 17791, 17810 n.134 (2007) (citation
omitted). An ―overbuilder‖ is a company that builds and
offers customers a competitive alternative where a
telecommunications company already operates. According to
the Complaint, Comcast eliminated competition by (1)
acquiring competitors in the Philadelphia market and

4
The ―Philadelphia cluster‖ and the ―Philadelphia DMA‖ are
separate terms. The Philadelphia DMA includes the cluster
counties as well as the counties of Lehigh and Northampton,
Pennsylvania. See App. 03614, 03795.

8
(2) swapping with competitors cable systems and subscribers
outside of the Philadelphia market for cable systems and
subscribers within the Philadelphia market. The Complaint
also alleged that Comcast engaged in conduct intended to
exclude competition from overbuilder RCN Telecom
Services, Inc. (―RCN‖), by denying it access to ―Comcast
Sportsnet,‖ requiring contractors to enter non-compete
agreements, and inducing potential customers to sign up for
long contracts with special discounts and penalty provisions
in the areas where RCN intended to overbuild. App. 00235-
239.

As a result of its clustering, Comcast allegedly harmed
the class by eliminating competition, raising entry barriers to
potential competition, maintaining increased prices for cable
services at supra-competitive levels, and depriving
subscribers of the lower prices that would result from
effective competition. App. 00241-242. In other words,
Comcast subscribers allegedly pay too much for their non-
basic video programming cable service.

B.

On May 3, 2007, after extensive motions practice, see
App. 00148-172 (listing 194 docket entries prior to
certification), the District Court certified the proposed class.
App. 00354. It determined that Plaintiffs had met the
requirements of Rule 23(a) of the Federal Rules of Civil
Procedure (numerosity, commonality, typicality, and
adequacy). App. 00366-372. It held also that Plaintiffs had
met the predominance and superiority requirements of Rule
23(b). App. 00373-387. We denied on June 29, 2007,
Comcast‘s 23(f) petition seeking interlocutory review.

9
 The Court also certified the Chicago class‘s claims, but
stayed them pending the outcome of the Philadelphia class.
App. 00177, 00179.5

Following our decision in Hydrogen Peroxide, 552
F.3d 305, the District Court granted in part Comcast‘s motion
to reconsider its Philadelphia certification decision (the Court
denied without prejudice consideration of the Chicago class
certification, again pending the outcome in Philadelphia).
App. 00437-439. It vacated only the portion of the
certification decision that addressed Rule 23(b)‘s
predominance requirement. The Court scheduled a hearing on
the issue of predominance as it related to (1) antitrust impact,
and (2) methodology of damages.

The District Court held an evidentiary hearing on
October 13-15 and 26, 2009. During the four-day hearing, the
Court heard live testimony from fact and expert witnesses,
considered 32 expert reports, and examined deposition
excerpts, as well as many other documents. Following the
hearing, the Court issued to the parties a series of questions
related to antitrust impact and damages methodology, and
heard argument on November 16, 2009, to address its specific
questions.

5
Plaintiffs‘ counsel also filed a complaint in the District of
Massachusetts on behalf of a ―Boston cluster.‖ That case was
transferred to the Eastern District of Pennsylvania, and has
been stayed pending resolution of the Chicago cluster claims.
See App. 00179.

10
 On January 7, 2010, the District Court recertified the
Philadelphia class, and issued an amended class certification
order on January 13, 2010. The Court reaffirmed and
incorporated its May 2007 certification as to numerosity,
commonality, typicality, and adequacy (Rule 23(a)), as well
as superiority (Rule 23(b)(3)). App. 00029. On the disputed
issue of predominance, the Court held that Plaintiffs had
demonstrated by a preponderance of the evidence that: (1)
questions of law and fact common to the members of the class
predominated; (2) the relevant geographic market could be
the Philadelphia Designated Market Area; (3) the class could
establish antitrust impact on the theory that Comcast‘s
clustering through the swaps and acquisitions deterred
overbuilder competition; (4) the models and analyses of
Plaintiffs‘ damages expert, Dr. James McClave, were
common evidence available to measure and quantify damages
on a class-wide basis; and (5) the class could establish
antitrust impact through common evidence applicable to all
class members. App. 00030. In certifying the class, however,
the District Court narrowed the class‘s various theories of
class-wide impact to a single theory:

Proof of antitrust impact relative to such claims
shall be limited to the theory that Comcast
engaged in anticompetitive clustering conduct,
the effect of which was to deter the entry of
overbuilders in the Philadelphia DMA.

App. 00032.

The Court accompanied its order with an 81-page
memorandum opinion containing its analysis of the evidence
presented at the evidentiary hearing. Behrend v. Comcast

11
Corp., 264 F.R.D. 150 (E.D. Pa. 2010). The Court
summarized its opinion as follows:

Having rigorously analyzed the expert reports,
as well as the testimony presented by the parties
during a four-day evidentiary hearing, we
conclude that the class has met its burden to
demonstrate that the element of antitrust impact
is capable of proof at trial through evidence that
is common to the class rather than individual to
its members, and that there is a common
methodology available to measure and quantify
damages on a class-wide basis.

Id. at 154.

Comcast filed a Rule 23(f) petition to appeal on
January 27, 2010. While that petition was pending, Comcast
moved for summary judgment. The class responded, and
Comcast filed a reply on June 4, 2010. We granted Comcast
permission to appeal on June 9, 2010. The motion for
summary judgment remains pending in the District Court.

II.

The District Court had jurisdiction pursuant to 28
U.S.C. §§ 1331 and 1337. We have jurisdiction pursuant to
28 U.S.C. § 1292(e) and Rule 23(f) of the Federal Rules of
Civil Procedure.

―We review a class certification order for abuse of
discretion, which occurs if the district court‘s decision rests
upon a clearly erroneous finding of fact, an errant conclusion

12
of law or an improper application of law to fact.‖ Hydrogen
Peroxide, 552 F.3d at 312 (citation and quotations omitted).
We review de novo whether an incorrect legal standard has
been used. Id. (citation omitted).

For a district court‘s finding of fact to be clearly
erroneous, the standard is high. ―Clearly erroneous‖ has been
interpreted to mean that a reviewing court can upset a finding
of fact, even if there is some evidence to support the finding,
only if the court is ―left with the definite and firm conviction
that a mistake has been committed.‖ United States v. U.S.
Gypsum Co., 333 U.S. 364, 395 (1948). This means that ―[i]t
is the responsibility of an appellate court to accept the
ultimate factual determination of the fact-finder unless that
determination either (1) is completely devoid of minimum
evidentiary support displaying some hue of credibility, or (2)
bears no rational relationship to the supportive evidentiary
data.‖ Krasnov v. Dinan, 465 F.2d 1298, 1302 (3d Cir. 1972).
Especially pertinent to the issue before us, the Supreme Court
has explained:

This standard plainly does not entitle a
reviewing court to reverse the finding of the
trier of fact simply because it is convinced that
it would have decided the case differently. . . .
In applying the clearly erroneous standard to the
findings of a district court sitting without a jury,
appellate courts must constantly have in mind
that their function is not to decide factual issues
de novo. If the district court‘s account of the
evidence is plausible in light of the record
viewed in its entirety, the court of appeals may
not reverse it even though convinced that had it

13
 been sitting as the trier of fact, it would have
weighed the evidence differently. Where there
are two permissible views of the evidence, the
factfinder‘s choice between them cannot be
clearly erroneous.

Anderson v. Bessemer City, 470 U.S. 564, 573-574 (1985)
(quotations and citations omitted); accord PA Prison Soc‘y v.
Cortes, 622 F.3d 215, 231 (3d Cir. 2010).

III.

Comcast raises three principal arguments on appeal,
urging us to overturn the District Court‘s certification order
on the grounds that: (1) the Court‘s finding that the class can
establish class-wide antitrust impact through common
evidence was incorrect for various reasons; (2) the District
Court exceeded its discretion in accepting Plaintiffs‘ proposed
methodology for damages calculation; and (3) the Court‘s
certification of a per se antitrust claim was clear error. In
response, Plaintiffs defend in all respects the District Court‘s
certification decision. We first outline the Rule 23 legal
framework and then analyze each of Comcast‘s contentions.

Rule 23 of the Federal Rules of Civil Procedure allows
a class action if certain requirements are met. First, the class
must meet the ―prerequisites‖ of Rule 23(a): numerosity,
commonality, typicality, and adequacy. Second, the class
must fit one of the Rule 23(b) types of classes. Here,
Plaintiffs seek certification under Rule 23(b)(3), which
requires (1) ―that the questions of law or fact common to class
members predominate over any questions affecting only
individual members,‖ and (2) ―that a class action is superior

14
to other available methods for fairly and efficiently
adjudicating the controversy.‖ Rule 23(b)(3). These
requirements are known as predominance and superiority.

The district court must conduct a ―rigorous analysis‖
of the evidence and arguments in making the class
certification decision. Hydrogen Peroxide, 552 F.3d at 318.
The analysis requires ―a thorough examination of the factual
and legal allegations‖ and ―may include a preliminary inquiry
into the merits.‖ Id. at 317 (quoting Newton v. Merrill Lynch,
Pierce, Fenner & Smith, Inc., 259 F.3d 154, 166, 168 (3d Cir.
2001)). We explained in Hydrogen Peroxide the permissible
extent of any inquiry into the merits:

[T]he requirements set out in Rule 23 are not
mere pleading rules. The court may delve
beyond the pleadings to determine whether the
requirements for class certification are satisfied.
. . . An overlap between a class certification
requirement and the merits of a claim is no
reason to decline to resolve relevant disputes
when necessary to determine whether a class
certification requirement is met. Some
uncertainty ensued when the Supreme Court
declared in Eisen v. Carlisle & Jacquelin, 417
U.S. 156, 177 (1974), that there is ―nothing in
either the language or history of Rule 23 that
gives a court any authority to conduct a
preliminary inquiry into the merits of a suit in
order to determine whether it may be
maintained as a class action.‖ Only a few years
later, in addressing whether a party may bring
an interlocutory appeal when a district court

15
 denies class certification, the Supreme Court
pointed out that ―the class determination
generally involves considerations that are
‗enmeshed in the factual and legal issues
comprising the plaintiff‘s cause of action.‘‖
[Coopers & Lybrand v.] Livesay, 437 U.S.
[463,] 469 [(1978)] (quoting Mercantile Nat‘l
Bank v. Langdeau, 371 U.S. 555, 558 (1963)).
As we explained in Newton, 259 F.3d at 166-
69, Eisen is best understood to preclude only a
merits inquiry that is not necessary to determine
a Rule 23 requirement. Other courts of appeals
have agreed.

552 F.3d at 316-317 (quotations and citations omitted).6
Accordingly, at the class certification stage, we are precluded
from addressing any merits inquiry unnecessary to making a
Rule 23 determination. Id. Further, any findings for the
purpose of class certification ―do not bind the fact-finder on
the merits.‖ Id. at 318.

Plaintiffs bear the burden of establishing each element
of Rule 23 by a preponderance of the evidence. Id. at 320
(―[T]o certify a class the district court must find that the
evidence more likely than not establishes each fact necessary
to meet the requirements of Rule 23.‖) (citation omitted). The

6
The Supreme Court confirmed our interpretation of the Rule
23 inquiry in Wal-Mart Stores, Inc. v. Dukes, 131 S. Ct. 2541
(2011). See id. at 2551, 2552 n.6 (stating that ―[f]requently
[the Rule 23] ‗rigorous analysis‘ will entail some overlap with
the merits of the plaintiff‘s underlying claim,‖ but Eisen still
prohibits ―a merits inquiry for any other pretrial purpose‖).

16
court must also examine critically expert testimony on both
sides and may be persuaded by either side as to whether a
certification requirement has been met. Id. at 323. Indeed,
―[w]eighing conflicting expert testimony at the certification
stage is not only permissible; it may be integral to the
rigorous analysis Rule 23 demands.‖ Id.

The parties dispute whether Plaintiffs have met the
predominance requirement. Predominance ―tests whether
proposed classes are sufficiently cohesive to warrant
adjudication by representation.‖ Amchem Prods., Inc. v.
Windsor, 521 U.S. 591, 623 (1997). It ―is a test readily met in
certain cases alleging consumer or securities fraud or
violations of the antitrust laws,‖ id. at 625, but a court may
not relax its certification analysis as to each element of Rule
23, see Hydrogen Peroxide, 552 F.3d at 322. To assess
whether common or individual issues predominate, a district
court must examine the nature of the evidence and ―formulate
some prediction as to how specific issues will play out . . . .‖
Id. at 311 (quotations and citations omitted).

Reviewing a district court‘s certification of a class, we
examine the elements of the class‘s claims ―through the
prism‖ of Rule 23. Id. (quoting Newton, 259 F.3d at 181).
The elements of the claims before us are (1) a violation of the
antitrust laws (here, sections 1 and 2 of the Sherman Act), (2)
individual injury resulting from that violation, and (3)
measurable damages. See id. Individual injury, also known as
antitrust impact, ―is critically important for the purpose of
evaluating Rule 23(b)(3)‘s predominance requirement
because it is an element of the claim that may call for
individual, as opposed to common, proof.‖ Id. At the class
certification stage, Plaintiffs‘ burden is ―to demonstrate that

17
the element of antitrust impact is capable of proof at trial
through evidence that is common to the class rather than
individual to its members.‖ Id. at 311-312.

IV.

Comcast devotes much of its energy to contending that
the District Court exceeded its discretion in holding that
Plaintiffs had established common evidence of antitrust
impact. It attacks this issue in two ways: first, that the District
Court failed to apply the correct legal standard for
determining the relevant geographic market, and, second, that
the District Court made clearly erroneous factual findings by
relying on Plaintiffs‘ expert for proof of class-wide antitrust
impact. We address each contention in turn.

A.

Before the District Court, Plaintiffs contended that the
relevant geographic market was the Philadelphia Designated
Market Area, whereas Comcast countered that it was each
individual‘s household. The District Court agreed with
Plaintiffs. Behrend, 264 F.R.D. at 160. Plaintiffs‘ expert, Dr.
Michael Williams, provided seven bases to support the
conclusion that the relevant geographic market was the
Philadelphia DMA. The District Court set forth each basis, as
well as Comcast‘s counterarguments. 264 F.R.D. at 157-160.
The Court stated that Comcast‘s focus on the individual
household was not supported by the record, and that setting
such a small market would be ―impractical and inefficient.‖
264 F.R.D. at 160. Instead, the Court noted that the alleged
conduct centered on Comcast‘s attempt to acquire
substantially all of the cable systems in the Philadelphia

18
DMA, and that the Federal Communications Commission
aggregates relevant geographic markets in which customers
face ―similar competitive choices.‖ 264 F.R.D. at 160. The
Court concluded, ―[T]he record evidence shows that
consumers throughout the DMA can face similar competitive
choices and suffer the same alleged antitrust impact resulting
from Comcast‘s clustering conduct in the Philadelphia
DMA.‖ 264 F.R.D. at 160.

Comcast contends that the Court failed to articulate or
apply the correct legal standard. According to Comcast, the
geographic market is defined in terms of consumer demand
substitutability—the area in which a buyer may look for the
goods or services he seeks. Because an individual can choose
only among providers offering video programming services to
his household, Comcast asserts that the geographic market
must be the household. Comcast contends additionally that
the Court improperly credited Dr. Williams‘s seven bases for
the geographic market because it later rejected three of the
seven theories, and that the Court‘s two stated reasons for
accepting the geographic market were irrelevant and
erroneous.

Plaintiffs respond at three levels. First, they contend
that they need not define the relevant geographic market: per
se claims do not require defining the geographic market, and
they offered direct evidence of market power, thereby
relieving them of the obligation to define the relevant
geographic market. Second, Plaintiffs state that the District
Court used the commercial realities test to determine the
relevant geographic market and did not ignore demand
substitutability. Third, according to Plaintiffs, Comcast
cannot demonstrate clear error in the Court‘s factual

19
determination that ―consumers throughout the [Philadelphia]
DMA can face similar competitive choices.‖ See Behrend,
264 F.R.D. at 160.

B.

We will affirm the District Court‘s conclusion that the
Philadelphia DMA is a relevant geographic market
―susceptible to proof at trial through available evidence
common to the class.‖ 264 F.R.D. at 160.

The relevant geographic market is a component of
substantive antitrust law. For antitrust claims analyzed
through the rule of reason, plaintiffs must demonstrate that
the defendant possessed market power in the relevant
geographic market. See Pa. Dental Ass‘n v. Med. Serv. Ass‘n
of Pa., 745 F.2d 248, 260 (3d Cir. 1984). For per se claims,
plaintiffs need not establish a geographic market. See In re
Ins. Brokerage Antitrust Litig., 618 F.3d 300, 316-317 (3d
Cir. 2010) (explaining that some prohibited practices can be
conclusively presumed to unreasonably restrain competition).
Additionally, ―direct proof of monopoly power does not
require a definition of the relevant market.‖ See Broadcom
Corp. v. Qualcomm Inc., 501 F.3d 297, 307 n.3 (3d Cir.
2007).

Defining the relevant geographic market, however, is
an issue of the merits. See, e.g., Borough of Lansdale v. Phila.
Elec. Co., 692 F.2d 307 (3d Cir. 1982) (addressing on appeal
whether jury verdict should be set aside because of allegedly
erroneous definition of relevant geographic market). At the
class certification stage, a court need only be satisfied that
issues—including the definition of a geographic market—will

20
be capable of proof through evidence common to the class.
See Hydrogen Peroxide, 552 F.3d at 311; IIA Phillip E.
Areeda et al., Antitrust Law ¶ 398b (3d ed. 2007) (describing
that at the class certification stage the plaintiffs‘ expert
typically concludes that ―any significant economic issues
underlying the class representative‘s antitrust claims,
including but not limited to issues regarding market definition
. . . will be analyzed and proven through the use of common
data and evidence that would be used to prove the claims of
the other members of the proposed Class‖) (emphasis added).
If the plaintiffs allege per se claims, they may still need to
persuade the district court that, in the event defining the
relevant geographic market becomes necessary, it is capable
of common proof. See Areeda et al., supra, ¶ 398b.

The inquiry before the District Court, therefore, was
whether Plaintiffs could demonstrate by a preponderance of
the evidence that they would be able to establish a relevant
geographic market capable of proof common to the class. The
District Court concluded it was: ―We conclude that Dr.
Williams‘ geographic market definition is susceptible to proof
at trial through available evidence common to the class.‖ 264
F.R.D. at 160. The parties dispute whether the District Court
properly defined the relevant geographic market—Comcast
contends it erred as a matter of law, and Plaintiffs respond
they need not establish a geographic market. These are merits
arguments, which are not properly before us. Our review is
limited to whether the Court exceeded its discretion in
determining that the class could establish through common
proof that the relevant geographic market could be the
Philadelphia DMA. We conclude it did not, legally or
factually.

21
 C.

First, we perceive no legal error in the District Court‘s
reasoning. Procedurally, it conducted the required ―rigorous
analysis‖ by examining in depth the expert opinions on both
sides and setting forth its conclusions. See Hydrogen
Peroxide, 552 F.3d at 317, 320. Substantively, the Court
determined that ―the record evidence shows that consumers
throughout the DMA can face similar competitive choices
and suffer the same alleged antitrust impact resulting from
Comcast‘s clustering conduct in the Philadelphia DMA.‖ 264
F.R.D. at 160. Comcast contends that the Court failed to
apply the consumer demand substitutability test, which
defines the relevant geographic market as ―that area in which
a potential buyer may rationally look for the goods or services
he seeks.‖ Gordon v. Lewiston Hosp., 423 F.3d 184, 212 (3d
Cir. 2005) (citing Pa. Dental Ass‘n, 745 F.2d at 260). We
determine otherwise: the Court‘s analysis of the relevant
geographic market for purposes of class certification
comported with our precedent.

―[I]dentification of the relevant geographic market is a
matter of analyzing competition.‖ Borough of Lansdale v.
Phila. Elec. Co., 692 F.2d 307, 311 (3d Cir. 1982). Defining it
―is a question of fact to be determined in the context of each
case in acknowledgment of the commercial realities of the
industry being considered.‖ Gordon, 423 F.3d at 212 (quoting
Borough of Lansdale, 692 F.2d at 311). In these decisions of
our Court, one of which has commanded our attention for
almost thirty years, we relied on two Supreme Court cases to
develop this standard: United States v. Grinnell Corp., 384
U.S. 563, 576 (1966), which held that the relevant geographic
market under the Sherman Act was ―not the several local

22
areas which the individual stations serve, but the broader
national market that reflects the reality of the way in which
they built and conduct their business,‖ and Tampa Electric
Co. v. Nashville Coal Co., 365 U.S. 320, 327, 332 (1961),
which defined the relevant geographic area for § 3 of the
Clayton Act, 15 U.S.C. § 3, as ―the market area in which the
seller operates, and to which the purchaser can practicably
turn for supplies‖ or as the area in which suppliers
―effectively compete.‖ In another Clayton Act case, the
Supreme Court stated: ―The geographic market selected must,
therefore, both correspond to the commercial realities of the
industry and be economically significant. Thus, although the
geographic market in some instances may encompass the
entire Nation, under other circumstances it may be as small as
a single metropolitan area.‖ Brown Shoe Co. v. United States,
370 U.S. 294, 336-337 (1962) (quotations and citations
omitted); see Grinnell, 384 U.S. at 572 (citing Brown Shoe as
analogous to determining the relevant market for the Sherman
Act).

D.

The District Court‘s determination—that consumers
―face similar competitive choices‖ in the Philadelphia DMA
as a result of Comcast‘s alleged clustering conduct—is
consistent with the above standards because it considers both
where a buyer may rationally look for goods and the
commercial reality of the industry. Comcast‘s insistence that
the geographic market must be the individual household (as
the only place where a consumer can ―comparison shop‖)
ignores that the geographic market must be ―economically
significant,‖ Brown Shoe Co., 370 U.S. at 336-337, and may
be premised on ―the commercial realities of the industry

23
being considered,‖ Borough of Lansdale, 692 F.2d at 311, the
area where suppliers ―effectively compete,‖ Tampa Electric
Co., 365 U.S. at 332, or the broader market reflecting the
reality of conducting business, Grinnell, 384 U.S. at 576.7 We
therefore discern no legal error in the District Court‘s
analysis.

E.

7
We note additionally the tension between the concept of a
―geographic market‖ and Comcast‘s conclusion that ―the
relevant geographic market . . . is each class member‘s
residence.‖ Appellants‘ Br. 15. As of 2009, Philadelphia
County alone had over 560,000 households. See U.S. Census
Bureau, Philadelphia County QuickFacts,
http://quickfacts.census.gov/qfd/states/42/42101.html.
Nationwide, in 2010 there were over 117 million households.
See U.S. Census Bureau, America‘s Families and Living
Arrangements: 2010,
http://www.census.gov/population/www/socdemo/hh-
fam/cps2010.html (Table AVG1). Taken at face value,
Comcast‘s assertion that there are millions of geographic
markets in the Philadelphia DMA (or over one hundred
million geographic markets nationwide for multichannel
video programming distributors) renders the phrase
―geographic market‖ nonsensical. Perhaps for this reason, our
research revealed no case—nor does Comcast provide one—
in which a geographic market has been set at the individual
household level. Cf. Brown Shoe, 370 U.S. at 337 (―Thus,
although the geographic market in some instances may
encompass the entire Nation, under other circumstances it
may be as small as a single metropolitan area.‖).

24
 Second, we recognize ample evidence in the record
supporting the District Court‘s factual findings underpinning
its market determination, which precludes us from reversing
those findings as clearly erroneous. See, e.g., EBC, Inc. v.
Clark Bldg. Sys. Inc., 618 F.3d 253, 273 (3d Cir. 2010) (―We
will not reverse ‗[i]f the district court‘s account of the
evidence is plausible in light of the record viewed in its
entirety‘ even if we would have weighed that evidence
differently.‖ (quoting Anderson, 470 U.S. at 573-574)). The
Court cited Dr. Williams‘s seven bases for drawing the
geographic market as the Philadelphia DMA. Behrend, 264
F.R.D. at 157-160. Although it rejected three of those bases,
the remaining four tended to show that Comcast‘s clustering
had anticompetitive effects in the Philadelphia DMA by
deterring overbuilders from entering the Designated Market
Area, and that the industry itself used DMAs to focus its
competition. Additional evidence in the record, reviewed in
detail below, demonstrated that clustering results in fewer
competitors and higher cable prices for the entire market.
This evidence belies Comcast‘s claim that there is no change
at the individual level when Comcast aggregates surrounding
franchises.

Simply put, the District Court determined by a
preponderance of the evidence that, when addressed on the
merits, the class may be able to prove through common
evidence that the relevant geographic market is the
Philadelphia DMA. This determination did not exceed the
Court‘s permissible discretion. To the extent Comcast reads
the Court‘s opinion as actually fixing the relevant geographic
market, we note that its determination was made solely for the

25
purposes of class certification and will not be binding on the
merits. See Hydrogen Peroxide, 552 F.3d at 318.8

8
The Concurring and Dissenting Opinion (―Concurrence-
Dissent‖) faults the parties, the District Court and this
Opinion for using ―equivocally‖ the phrase ―relevant
geographic market.‖ Slip Concurring-Dissenting Op. at 8.
Specifically, it asserts that this Opinion ―assumes . . . that the
class is properly defined to cover the Philadelphia DMA
. . . .‖ Id. at 10. The Concurrence-Dissent misunderstands an
important distinction: as noted supra footnote 4, Plaintiffs
have alleged a ―class region‖ (to borrow from the
Concurrence-Dissent‘s terminology) of a ―Philadelphia
cluster,‖ which is distinct from the contested relevant
geographic market of the ―Philadelphia DMA.‖ Our
―assumption‖ concerning the ―class region‖ is an uncontested
piece of Plaintiffs‘ case: Comcast appeals only the precise
issue of whether the District Court applied a correct legal
standard in determining that the substantive antitrust
geographic market could be established by evidence common
to the class, not whether the ―Philadelphia cluster‖ is an
appropriate ―class region.‖ See Appellants‘ Br. at 15 (labeling
the issue as: ―The District Court Failed To Apply The Correct
Legal Standard In Its Ruling On Plaintiffs‘ Geographic
Market Definition‖); id. at 20 (summarizing that ―the alleged
geographic market accepted by the district court is wholly
divorced from the legal standard for determining the correct
geographic market‖). Accordingly, when the Concurrence-
Dissent states, ―A compelling argument could be made . . .,‖
Slip Concurring-Dissenting Op. at 11 (emphasis added), it
goes beyond our role as a reviewing court by raising and
addressing an argument not before us. See, e.g., AT & T v.
F.C.C., 582 F.3d 490, 495 (3d Cir. 2009) (―An appellant

26
 V.

Comcast hinges its next line of arguments on the
District Court‘s final certification: ―Proof of antitrust impact
relative to such claims shall be limited to the theory that
Comcast engaged in anticompetitive clustering conduct, the
effect of which was to deter the entry of overbuilders in the
Philadelphia DMA.‖ App. 00032. According to Comcast, the
District Court made clearly erroneous findings of fact by
relying on Plaintiffs‘ expert, Dr. Williams, in support of the
certified theory of antitrust impact.

The District Court considered in great detail the
arguments presented by both sides. It rejected three of
Plaintiffs‘ four theories of class-wide impact. Behrend, 264
F.R.D. at 166 (rejecting theory of direct broadcast satellite
(―DBS‖) foreclosure); id. at 177-178 (rejecting benchmark
theory); id. at 181 (rejecting bargaining power theory).
Nonetheless, it accepted that Plaintiffs could establish class-
wide antitrust impact on the theory of clustering and its
impact on overbuilder competition. After detailing the
evidence put forth by both sides, id. at 166-174, the Court
concluded that ―the Class has met its burden to demonstrate
that the anticompetitive effect of clustering on overbuilder
competition is capable of proof at trial through evidence that
is common to the class,‖ id. at 174. The Court found that
through the model of Plaintiffs‘ expert, Dr. Williams, and the
empirical studies conducted by governmental agencies and

waives an argument in support of reversal if he does not raise
that argument in his opening brief.‖), rev‘d on other grounds,
131 S. Ct. 1177 (2011).

27
private researchers, the class had shown that the presence of
an overbuilder constrains cable prices, and that Comcast
engaged in conduct designed to deter the entry of
overbuilders in the Philadelphia DMA. Id. at 174. It found
unpersuasive the conclusions of Comcast‘s expert, Dr. David
J. Teece, that overbuilding is not a successful business model.
Id. at 174-175.

A.

On appeal, Comcast constructs a four-tiered argument
to support its objections. First, it contends that Plaintiffs
cannot show class-wide antitrust impact based on potential
overbuilding by any of the ―Transaction parties.‖9 According
to Comcast, the evidence demonstrated there was no actual
competition between the Transaction parties; Plaintiffs
therefore must show that the challenged conduct eliminated
potential competition. In Comcast‘s view, the record evidence
reflects that no Transaction parties had taken any affirmative
steps to overbuild and, consequently, there was no potential
competition to eliminate. Second, Comcast contends that
Plaintiffs identified only RCN Telecom Services, Inc., as
attempting to overbuild in the Philadelphia DMA. The
evidence establishes, according to Comcast, that RCN was
not going to overbuild as a result of its own financial woes,
not as a result of any alleged activity on the part of Comcast.

9
As detailed supra note 2, the ―Transaction parties‖ are the
parties that Comcast acquired or with which it swapped cable
systems, which include: Marcus Cable; Greater Philadelphia
Cablevision, Inc.; Lenfest Communications, Inc.; AT&T;
Adelphia Communications Corp.; Time Warner; and Patriot
Media.

28
Third, as the argument goes, because there was no record
evidence demonstrating actual or potential competition, the
theoretical opinions indicating otherwise rendered by
Plaintiffs‘ expert, Dr. Williams, were clearly erroneous.
Comcast disputes at many levels Dr. Williams‘s methodology
and results in his ―market structure‖ and ―market
performance‖ opinions. Summed up, Comcast contends that
theoretical expert opinions are no replacement for market
facts, the record evidence showed no actual or potential
overbuilding (as addressed in the first two contentions), and
therefore any reliance on the expert opinions for evidence of
anticompetitive behavior was clearly erroneous. Fourth,
Comcast adds that any evidence of anticompetitive conduct
specific to Delaware County could not serve as evidence of
class-wide impact for the Philadelphia cluster.

B.

Plaintiffs respond to each level of Comcast‘s position.
First, citing many portions of the record, they assert that there
is ―overwhelming‖ record evidence that Comcast‘s clustering
of the Philadelphia DMA deterred and reduced overbuilding
competition, resulting in antitrust impact (higher cable prices)
for all class members. According to the class, the record
demonstrates: clustering deters overbuilding, the swaps and
acquisitions eliminated competition, Multi-System Operators
(―MSOs‖) actually do overbuild one another, Comcast and
other MSOs look to one another‘s prices to set their own, and
the MSOs chose affirmatively not to compete. The class adds
that Comcast is raising a merits argument by asking the Court
to consider the ―potential competition‖ doctrine. Second,
Plaintiffs contend that Comcast raises a merits issue by asking
the Court to examine whether Comcast‘s conduct in fact

29
prevented RCN from overbuilding in more areas than it did.
In any event, they state that the record evidence demonstrates
RCN had the intent and capital to overbuild the Philadelphia
market. Third, Plaintiffs state that Dr. Williams‘s theoretical
model plainly shows common evidence of class-wide impact;
Comcast‘s contention that Dr. Williams‘s opinions do not
prove antitrust impact is one for the jury to decide on the
merits. Fourth, the evidence related to Delaware County
―adds to and illustrates‖ the common evidence of Comcast‘s
anticompetitive clustering conduct.

VI.

We begin the analysis of these contentions by focusing
on the precise inquiry:

Plaintiffs‘ burden at the class certification stage
is not to prove the element of antitrust impact,
although in order to prevail on the merits each
class member must do so. Instead, the task for
plaintiffs at class certification is to demonstrate
that the element of antitrust impact is capable of
proof at trial through evidence that is common
to the class rather than individual to its
members.

Hydrogen Peroxide, 552 F.3d at 311-312 (emphasis added).
Many of Comcast‘s contentions ask us to reach into the
record and determine whether Plaintiffs actually have proven
antitrust impact. This we will not do. Instead, we inquire
whether the District Court exceeded its discretion by finding
that Plaintiffs had demonstrated by a preponderance of the

30
evidence that they could prove antitrust impact through
common evidence at trial.

This dispute therefore is evidentiary. When facts are at
issue, the District Court exceeds its discretion in certifying a
class only if its findings are clearly erroneous. Id. at 312.
Comcast bears a heavy burden in convincing us that the
District Court‘s factual findings were clearly erroneous. See
Anderson, 470 U.S. at 573-574 (―If the district court‘s
account of the evidence is plausible in light of the record
viewed in its entirety, the court of appeals may not reverse it .
. . .‖); Krasnov, 465 F.2d at 1302 (―It is the responsibility of
an appellate court to accept the ultimate factual determination
of the fact-finder unless that determination either (1) is
completely devoid of minimum evidentiary support
displaying some hue of credibility, or (2) bears no rational
relationship to the supportive evidentiary data.‖).

Comcast has not carried its burden. Plaintiffs provided
evidence at the certification hearing that tended to show that
Comcast‘s clustering (through swaps and acquisitions)
reduced competition, deterred the entry of overbuilders, and
resulted in higher cable prices for the entire class. This
evidence displays ―some hue of credibility‖ and bears a
rational relationship to the Court‘s finding. See Krasnov, 465
F.2d at 1302.

For example, one of Plaintiffs‘ experts, Dr. Williams,
concluded after a detailed analysis that, inter alia, Comcast‘s
clustering increased its market share and, consequently, its
market power, thereby raising barriers to entry for other
multichannel video programming distributors and resulting in
higher cable rates for all members of the class. App. 03599-

31
3600; see also Behrend, 264 F.R.D. at 166-171 (providing in
great detail the analyses, evidentiary support, and conclusions
of Dr. Williams). Dr. Williams also cited to Federal
Communications Commission reports, Government
Accountability Office reports, and academic research, all of
which indicated that reducing competition by clustering leads
to higher cable rates. App. 03663-3668. Another expert, Dr.
Hal Singer, used extensive record evidence to analyze how
Comcast‘s clustering denied overbuilders access to the
Philadelphia DMA. App. 03501-3529. Dr. Singer concluded
that Comcast‘s actions allowed it to foreclose competitors and
elevate prices. App. 03450. He also referenced multiple
studies—both governmental and private, some of which
overlapped with those referenced by Dr. Williams—that
concluded that cable prices are lower when overbuilder
competition is present. App. 03537-3548. Also in the record
are specific instances of Multi-System Operators attempting
to overbuild one another around the country. See Appellees‘
Br. 27 n.17 (citing 13 distinct examples in the record of
MSOs overbuilding one another).

All of this evidence demonstrates that Comcast‘s
alleged clustering conduct indeed could have reduced
competition, raised barriers to market entry by an overbuilder,
and resulted in higher cable prices to all of its subscribers in
the Philadelphia Designated Market Area. Based on this
evidence, we determine that the antitrust impact Plaintiffs
allege is ―plausible in theory‖ and ―susceptible to proof at
trial through available evidence common to the class.‖
Hydrogen Peroxide, 552 F.3d at 325; see also In re
Linerboard Antitrust Litig., 305 F.3d 145, 158 (3d Cir. 2002)
(holding that common issues predominated sufficient for class
certification when plaintiffs allegedly ―were all affected by

32
the increased price‖ they paid for linerboard). We are
satisfied that the District Court‘s findings were supported by
the evidence and were not clearly erroneous.

Comcast protests that the record demonstrates that
there was no actual or potential competition among the
Transaction parties. In light of the above record evidence,
however, Comcast‘s interpretation of the evidence does not
render the District Court‘s findings clearly erroneous.
Comcast remains free to make these arguments to the jury.

VII.

Comcast‘s other contentions are equally unpersuasive.
There is conflicting evidence as to the role Comcast played in
RCN Telecom Services, Inc.‘s decision to not overbuild
further in the Philadelphia DMA. Plaintiffs highlight record
evidence that RCN had the intent and capital necessary to
overbuild the Philadelphia market. Appellees‘ Br. 34-35.
Comcast contends instead that RCN faced financial woes, as
a result of which it abandoned its plans to overbuild.
Appellants‘ Br. 24-28. The District Court credited Plaintiffs‘
explanation: ―What Dr. Teece considers ‗unlikely,‘ Dr. Singer
considers to be the common evidence of antitrust impact,
namely that RCN was stymied in its efforts by Comcast‘s
predatory behavior.‖ Behrend, 264 F.R.D. at 175. Again, we
are satisfied that the District Court‘s finding was not clearly
erroneous. ―Where there are two permissible views of the
evidence, the factfinder‘s choice between them cannot be
clearly erroneous.‖ Anderson, 470 U.S. at 574. Here there are
two permissible views of the evidence and we will not disturb
the District Court‘s finding.

33
 Similarly, Comcast contends that Dr. Williams‘s
analysis and methodology was flawed for various reasons,
including the allegation that it was unsupported by any actual
evidence. We disagree. As detailed above, there was ample
evidence that clustering conduct can deter entry of
overbuilders and result in higher cable prices. Dr. Williams
and Dr. Singer examined evidence specific to Comcast‘s
activities in the Philadelphia market, as well as numerous
independent studies on the effects of cable clustering, to reach
their conclusions. Comcast cites various cases for the
proposition that ―expert theory is not a substitute for market
facts.‖ See, e.g., Brooke Grp. Ltd. v. Brown & Williamson
Tobacco Corp., 509 U.S. 209, 242 (1993) (expert opinion
rendered unreasonable by indisputable record facts); In re
New Motor Vehicles Canadian Export Antitrust Litig., 522
F.3d 6, 27 (1st Cir. 2008) (expert analysis unfinished and
―purely conclusory‖); In re Baby Food Antitrust Litig., 166
F.3d 112, 135 (3d Cir. 1999) (―An expert opinion based on . .
. meager superficial information . . . is highly speculative,
unreliable, and of dubious admissibility.‖). Although
expressing a correct legal precept, those cases addressed
situations in which the experts largely failed to tie their
theories to any evidence; the precept therefore does not apply
to this case in which the experts‘ theories were based on and
correlated to other record evidence.

Comcast also asserts that every individual had one or
two options from which to choose cable and that
consequently only the name of the provider changed, not the
number of options. This assertion completely overlooks the
nature of the claims of the class: by clustering, Comcast was
able to deter the entry of overbuilders, which resulted in
higher prices for all non-basic Comcast subscribers. And

34
Plaintiffs provided evidence that clustering can have this
effect. In short, the District Court‘s task was to weigh expert
testimony and make a determination, Hydrogen Peroxide, 552
F.3d at 323, and we discern no error in the Court‘s
determination that Dr. Williams‘s analysis demonstrated that
class-wide antitrust impact was susceptible to common proof.

As to Comcast‘s remaining contention that the District
Court erred by crediting as evidence of class-wide impact the
alleged conduct targeted at RCN Telecom Services, Inc., in
Delaware County, we agree with the class that the alleged
conduct is relevant to establishing class-wide impact. We
have explained that ―courts must look to the monopolist‘s
conduct taken as a whole rather than considering each aspect
in isolation.‖ LePage‘s Inc. v. 3M, 324 F.3d 141, 162 (3d Cir.
2003) (en banc) (citing Cont‘l Ore Co. v. Union Carbide &
Carbon Corp., 370 U.S. 690, 699 (1962)). Alleged specific
conduct aimed at preventing the entry of an overbuilder
anywhere in the Philadelphia DMA supports Plaintiffs‘
allegations of Comcast‘s ability to maintain supra-
competitive prices for the entire market.

VIII.

At bottom, Comcast misconstrues our role at this stage
of the litigation. Comcast would have us decide on the merits
whether there was actual or potential competition among the
Transaction parties, the reason RCN Telecom Services, Inc.,
abandoned the Philadelphia market, and whether Plaintiffs‘
experts proved antitrust impact. We are not the jury. Although
in Hydrogen Peroxide we heightened the inquiry a district
court must perform on the issue of class certification, nothing
in that opinion indicated that class certification hearings were

35
to become actual trials in which factual disputes are to be
resolved. Indeed, as we explained in Hydrogen Peroxide, a
district court may inquire into the merits only insofar as it is
―necessary‖ to determine whether a class certification
requirement is met. 552 F.3d at 316. Eisen still precludes any
further inquiry. See Eisen, 417 U.S. at 178 (―[T]he question is
not whether the plaintiff or plaintiffs . . . will prevail on the
merits, but rather whether the requirements of Rule 23 are
met.‖ (quoting Judge Wisdom‘s holding in Miller v. Mackey
Int‘l, Inc., 452 F.2d 424, 427 (5th Cir. 1971))); Hydrogen
Peroxide, 552 F.3d at 317 (―Eisen is best understood to
preclude only a merits inquiry that is not necessary to
determine a Rule 23 requirement.‖). We allow preliminary
merits inquiries when necessary for Rule 23 because of the
potentially ―decisive effect on litigation‖ of a certification
decision, Newton, 259 F.3d at 167, but those inquiries remain
limited and non-binding on the merits at trial, Hydrogen
Peroxide, 552 F.3d at 318. Nothing in Hydrogen Peroxide
requires plaintiffs to prove their case at the class certification
stage; to the contrary, they must establish by a preponderance
that their case is one that meets each requirement of Rule 23.
To require more contravenes Eisen and runs dangerously
close to stepping on the toes of the Seventh Amendment by
preempting the jury‘s factual findings with our own.10

10
Indeed, recent scholarship uniformly has expressed concern
over the trend towards converting certification decisions into
mini trials. See Joshua P. Davis & Eric L. Cramer, Antitrust,
Class Certification, and the Politics of Procedure, 17 Geo.
Mason L. Rev. 969, 970 (2010) (contending that the ―judicial
tendency to impose requirements at class certification‖ serves
no legitimate purpose and risks violating the Seventh
Amendment); Michael J. Kaufman & John M. Wunderlich,

36
 In sum, we hold that the District Court‘s
determination—that Plaintiffs have demonstrated by a
preponderance of the evidence that they can establish class-
wide antitrust impact through common evidence—did not
exceed its discretion.

IX.

To satisfy another portion of the predominance
requirement, Plaintiffs must establish that the alleged
damages are capable of measurement on a class-wide basis
using common proof. See Hydrogen Peroxide, 552 F.3d at
311, 325-326; cf. Newton v. Merrill Lynch, Pierce, Fenner &

The Unjustified Judicial Creation of Class Certification
Merits Trials in Securities Fraud Actions, 43 U. Mich. J.L.
Reform 323, 323 (2010) (stating that judicial resolution of
merits at the certification stage precludes victims from
obtaining redress, infringes on the Seventh Amendment, and
serves no legitimate policy concerns); Steig D. Olson,
―Chipping Away‖: The Misguided Trend Toward Resolving
Merits Disputes as Part of the Class Certification Calculus, 43
U.S.F. L. Rev. 935, 940 (2009) (intensifying the Rule 23
analysis is inconsistent with the Rule itself and highly
inefficient); J. Douglas Richards & Benjamin D. Brown,
Predominance of Common Questions – Common Mistakes in
Applying the Class Action Standard, 41 Rutgers L.J. 163, 169
(2009) (contending, inter alia, that requiring the district court
to determine by a preponderance whether plaintiffs‘ proposed
proof is actually correct or incorrect would ―substitute a
court‘s own evaluation of key merits questions for that of the
jury‖).

37
Smith, Inc., 259 F.3d 154, 187 (3d Cir. 2001) (stating that the
―Herculean task‖ of calculating individual damages from
hundreds of millions of different transactions ―counsels
against finding predominance‖). The District Court concluded
that Plaintiffs, through their expert Dr. McClave, provided a
damages model based on a common methodology available to
measure and quantify damages on a class-wide basis. 264
F.R.D. at 191. Comcast assails that determination as an abuse
of discretion.

A.

The District Court examined the methodology,
conclusions, and criticisms of the experts on both sides,
before providing its conclusions. 264 F.R.D. at 181-191.
(Comcast does not contest that the Court performed the
―rigorous analysis‖ required by Hydrogen Peroxide.) Because
on appeal Comcast renews the arguments it made to the
District Court, we set forth each side‘s position in the District
Court and the Court‘s response.

Plaintiffs‘ damages expert, Dr. McClave, concluded
that the prices in the Philadelphia market were consistently
and substantially higher than the prices in areas of effective
competition. 264 F.R.D. at 181. His econometric analysis
demonstrated that the alleged antitrust impact was class-wide,
because the prices were elevated above competitive levels
across all class members and for the entire time period. Id.
For his methods, Dr. McClave constructed ―but-for‖ prices
against which to compare the prices Comcast charged in the
Philadelphia DMA. ―But-for‖ prices are those that would
have existed absent the alleged anticompetitive conduct. To
construct the ―but-for‖ prices, he first selected comparable

38
―benchmark‖ counties around the country by applying two
―screens‖ to determine whether the counties represented a
level of competition similar to what Comcast would have
faced in the Philadelphia market absent its alleged
anticompetitive conduct. It is important to understand these
two screens. The first screen—the ―market share screen‖ or
―40% screen‖—required that the county have a Comcast
subscriber penetration rate of less than 40%. App. 03410. Dr.
McClave chose 40% because it represented the approximate
midpoint of Comcast‘s penetration rate in the Philadelphia
DMA (between approximately 20% in 1998 and 60% from
2003 through 2008). He chose this number also because it
allowed for growth during the class period but focused on
markets where Comcast was likely to have less market power
than it does in the Philadelphia market. Id. The second
screen—the ―Direct Broadcast Satellite screen‖, or ―DBS
screen‖—required that the county be in a Designated Market
Area where the penetration level for Alternative Delivery
Systems (which essentially includes DBS, but also master
antenna systems and multipoint distribution systems) was at
or higher than the national average of Alternative Delivery
Systems penetration rates in Comcast markets.11 Using data

11
Dr. McClave used Alternative Delivery Systems
penetration rates as a proxy to measure Direct Broadcast
Satellite penetration rates. App. 03410 n.11. Comcast‘s
expert, Dr. Chipty, referred to the screen as the ―DBS
screen,‖ and as measuring DBS penetration rates. App.
03834. The parties and District Court have continued using
the DBS terminology. Although the screen technically
measured Alternative Delivery Systems penetration rates, we
will use the parties‘ terminology and refer to it as the ―DBS

39
from the counties that fit the two screens, Dr. McClave
performed a multiple regression analysis to compare actual
prices in the Philadelphia DMA to the estimated ―but-for‖
prices. He then applied the overcharge percentage to the
relevant revenue obtained by Comcast for expanded basic
service in the Philadelphia market during the class period to
reach a final conservative estimated overcharge value:
$875,576,662.

Comcast‘s experts, Dr. Teece and Dr. Tasneem Chipty,
contested several parts of Dr. McClave‘s methodology, and
questioned his results. 264 F.R.D. at 183. First, they
challenged both benchmark screens used by Dr. McClave.
Regarding the ―DBS screen,‖ Dr. Teece asserted that Dr.
McClave erroneously chose the higher national Direct
Broadcast Satellite penetration rate, instead of the lower
regional rate predicted by Plaintiffs‘ experts Dr. Singer and
Dr. Williams. The District Court rejected the critique, stating
that Dr. McClave ―used his national average DBS penetration
screen as a descriptor of typical competitive market
conditions,‖ and was not attempting to predict the Direct
Broadcast Satellite penetration rate of the Philadelphia DMA.
Id. at 184. Regarding the ―market share screen,‖ Dr. Chipty
contended that because Comcast was present in only a few
counties in 1999, its actual market share was much higher in
the counties where it was and 0% where it was not; as a
result, the less-than-40% penetration rate provided an
inappropriate screen. App. 03833. The District Court rejected
the criticism as unsupported by the record, stating that Dr.
Chipty should have presented evidentiary data to show that

screen‖ and as measuring Direct Broadcast Satellite
penetration rates.

40
40% was an incorrect midpoint estimate or average rate. 264
F.R.D. at 184. The Court also noted that the 40% screen was
supported by the evidence as Comcast‘s approximate share of
the Philadelphia DMA at the midpoint of the class period. Id.
at 184 n.43.

Second, Dr. Chipty faulted Dr. McClave‘s model for
failing to consider properly demographic variables among the
counties: specifically, for omitting the variables of population
density and the number and type of households. The District
Court credited as well-supported Dr. McClave‘s response as
to why he omitted population density: it is correlated with
medium household income (which he included) and using it
as well as household income would create confounding and
unreliable results. 264 F.R.D. at 185-186. Additionally,
according to Dr. McClave, adding it would mask the effects
of anticompetitive influences because higher population
density results in lower costs per subscriber. Id. at 185. The
Court noted that Dr. Chipty‘s use of population density as a
variable resulted in it being positive and statistically
significant in one model but negative and statistically
significant in another. Id. at 186. Moreover, the Court added
that Federal Communications Commission and Government
Accountability Office studies included population density but
found it was not a statistically significant variable. Id.

Third, Dr. Chipty criticized Dr. McClave‘s model for
comparing list prices for expanded basic cable in the
Philadelphia DMA against the benchmark counties. She
opined that Dr. McClave‘s model did not take into account
the significant number of promotions and discounts offered to
Comcast customers. Id. at 187. Dr. Chipty offered several
rebuttal models that included population density and

41
discounted prices, which resulted in significantly lower or
even negative damages. The Court rejected Dr. Chipty‘s
models as ―suffer[ing] significant flaws.‖ Id. at 188, 189. It
stated that Dr. McClave‘s model accounted for discount
prices in the formula (not model) when he multiplied
anticompetitive overcharge by Comcast‘s relevant revenues
(because Comcast receives revenue only for prices charged,
the revenue side of the formula by definition includes
discount prices). Accordingly, by adding discount prices to
the model as well, Dr. Chipty‘s model doubly counted the
discount. The Court also noted that, as Dr. McClave
explained, more than 80% of Comcast‘s customers pay list
price for expanded basic cable, and discounts from list prices
are temporary (after which they return to list price). As to
another of Dr. Chipty‘s models, which calculated damages
through direct calculations instead of multiple regression, the
Court rejected it in the words of Dr. McClave as a ―novel and
non-standard formula for calculating damages.‖ Id. at 189.

Fourth, the District Court rejected Dr. Chipty‘s attempt
to impeach Dr. McClave‘s model by using it to calculate
damages for basic cable prices, instead of expanded basic
cable. Id. at 190. The Court explained that Dr. McClave‘s
model aimed to analyze only expanded basic cable, because
Comcast alters its prices at the expanded level, so ―any
application of the McClave model to [basic cable prices]
explains nothing.‖ Id. Comcast does not contest that ruling.

Fifth and finally, the Court asked the parties after the
hearing how to interpret Dr. McClave‘s damages model if it
credited at least one, but not all, of Dr. Williams‘s four
theories of antitrust impact. Id. It determined that Dr.
McClave‘s damages model was still viable, even if it rejected

42
some theories of antitrust impact, explaining that Dr.
McClave selected benchmarks to isolate the effect of
anticompetitive conduct, and that his use of the DBS screen
was ―entirely unrelated‖ to Dr. Williams‘s DBS foreclosure
theory. Id. The Court concluded that Dr. Williams‘s theories
of antitrust impact were not relevant to Dr. McClave‘s
methods of choosing benchmarks because ―[a]ny
anticompetitive conduct is reflected in the Philadelphia DMA
price, not in the selection of the comparison counties.‖ Id. at
191.

B.

Comcast contends that the District Court exceeded its
discretion in accepting Plaintiffs‘ proposed damages
calculation methodology. Its arguments are recast versions of
those rejected by the District Court. First, Comcast contends
that Dr. McClave‘s damages theory was based on all of
Plaintiffs‘ alleged anticompetitive effects, but the District
Court rejected three of Plaintiffs‘ four theories. Because Dr.
McClave stated that his model was based on the cumulative
effect and could not isolate damages for individual theories of
harm, according to Comcast the District Court erred in
accepting the damages model. Second, Comcast asserts that
the economic assumptions underlying the damages model
lack foundation in the record evidence. According to
Comcast, both screens employed by Dr. McClave are
factually unsupported and economically unsound: the ―DBS
penetration screen‖ because the Court rejected Dr. Williams‘s
Direct Broadcast Satellite foreclosure theory, and the ―market
share screen‖ because it bears no relation to the conditions
that would have existed in the Philadelphia region but for the
complained-of conduct. Third, Comcast contends that the

43
damages model is flawed because it fails to include
population density as a variable, and because it calculates
damages based on list prices, which fails to consider the
discounted prices that some subscribers actually pay.12

Plaintiffs remind us that the District Court already
thoroughly considered and rebutted each of the points that
Comcast now raises. As to the specific contentions, first, the
class asserts that the District Court explicitly held that Dr.
McClave‘s model was suitable for calculation of damages on
all or individual theories of liability. Second, the class
emphasizes that the damages model provides a methodology
that can establish damages on a class-wide basis using
common proof, and that Comcast ignores the proper inquiry
at class certification and instead prematurely attacks the
merits of the model. As a result, Comcast‘s arguments
concerning the benchmarks miss the point. Third, the class
asserts that Dr. McClave had ample justification to omit
population density as a variable, and that the damages model
incorporates discount prices.

X.

12
Following the Supreme Court‘s decision in Wal-Mart,
Comcast added that Dr. McClave‘s damages model, like the
expert model in Wal-Mart, could be ―safely disregard[ed].‖
See Wal-Mart, 131 S. Ct. at 2554. We disagree. The factual
and legal underpinnings of Wal-Mart—which involved a
massive discrimination class action and different sections of
Rule 23—are clearly distinct from those of this case. Wal-
Mart therefore neither guides nor governs the dispute before
us.

44
 We pause to identify the forest for the trees. If allowed
to proceed to trial, the class must establish that the injury it
suffered from the violation of the antitrust laws is measurable.
See Hydrogen Peroxide, 552 F.3d at 311; see also Newton,
259 F.3d at 188 (―Proof of injury (whether or not an injury
occurred at all) must be distinguished from calculation of
damages (which determines the actual value of the injury).‖).
The usual measure in an overcharge case ―is the difference
between the illegal price that was actually charged and the
price that would have been charged ‗but for‘ the violation
multiplied by the number of units purchased.‖ Areeda et al.,
supra, ¶ 392a. Given the inherent difficulty of identifying a
―but-for world,‖ we do not require that damages be measured
with certainty, but rather that they be demonstrated as ―a
matter of just and reasonable inference.‖ Story Parchment Co.
v. Paterson Parchment Paper Co., 282 U.S. 555, 563 (1931)
(―[W]hile the damages may not be determined by mere
speculation or guess, it will be enough if the evidence show
the extent of the damages as a matter of just and reasonable
inference . . . .‖); see also Stelwagon Mfg. Co. v. Tarmac
Roofing Sys., Inc., 63 F.3d 1267, 1273 (3d Cir. 1995) (citing
Story Parchment and explaining that ―damage issues in these
cases are rarely susceptible to the kind of concrete, detailed
proof of injury which is available in other contexts‖).

The inquiry for a district court at the class certification
stage is whether the plaintiffs have demonstrated by a
preponderance of the evidence that they will be able to
measure damages on a class-wide basis using common proof.
See Hydrogen Peroxide, 552 F.3d at 325. Some variation of
damages among class members does not defeat certification.
See 7AA Charles Alan Wright et al., Federal Practice and
Procedure § 1781 (3d ed. 2005) (stating for antitrust class

45
certification that ―it uniformly has been held that differences
among the members as to the amount of damages incurred
does not mean that a class action would be inappropriate.‖).
Complex and individual questions of damages, however,
weigh against finding predominance. Compare Newton, 259
F.3d at 187 (reasoning that having to examine proof of the
circumstances of hundreds of millions of individual
transactions counseled against finding predominance), with
Linerboard, 305 F.3d at 157-158 (determining that, in contrast
to Newton, all purchasers were affected by the increased
price). As the Court of Appeals for the First Circuit
explained:

It is true that the validity of plaintiffs‘ theory is
a common disputed issue. It will be for the fact
finder to decide whether this theory is
persuasive. At the class certification stage,
however, the district court must still ensure that
the plaintiffs‘ presentation of their case will be
through means amenable to the class action
mechanism. We are looking here not for hard
factual proof, but for a more thorough
explanation of how the pivotal evidence behind
plaintiff‘s theory can be established. If there is
no realistic means of proof, many resources will
be wasted setting up a trial that plaintiffs cannot
win.

In re New Motor Vehicles Canadian Export Antitrust Litig.,
522 F.3d 6, 29 (1st Cir. 2008) (citation omitted); see also
Areeda et al., supra, ¶ 331 (explaining for the issue of

46
damages that ―courts will not permit class actions unless they
can devise a practical means for their litigation‖).13

13
In response to the Concurrence-Dissent‘s position that
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579
(1993), applies at the stage of class certification, see Slip
Concurrence-Dissent Op. at 16, we make two observations.
First, as the Opinion acknowledges, ―in neither the District
Court nor before us‖ did Comcast raise this issue, id. at 17
n.18, and it is therefore not properly before us. Second,
although the Supreme Court recently hinted that Daubert may
apply for evaluating expert testimony at the class certification
stage, it need not turn class certification into a mini-trial.
Wal-Mart, 131 S. Ct. at 2553-54. We understand the Court‘s
observation to require a district court to evaluate whether an
expert is presenting a model which could evolve to become
admissible evidence, and not requiring a district court to
determine if a model is perfect at the certification stage. This
is consistent with our jurisprudence which requires that at
class certification stage, we evaluate expert models to
determine whether the theory of proof is plausible. Hydrogen
Peroxide, 552 F.3d at 324. ―[I]f such impact is plausible in
theory, it is also susceptible to proof at trial through available
evidence common to the class. When the latter issue is
genuinely disputed, the district court must resolve it after
considering all relevant evidence.‖ Id. at 325. When plaintiffs
present multiple models created by expert witnesses that can
show common evidence and those models are based on data,
a district court does not have to determine which model
should be used at the time of class certification. Linerboard,
305 F.3d at 155. Here, the District Court likely determined
that Dr. McClave‘s model could be refined between the time

47
 On appeal, the inquiry narrows. Because the District
Court held that Plaintiffs had established they could measure
damages through common proof, we examine whether that
determination was beyond the Court‘s discretion. Having
identified the forest of law, we proceed to scrutinize the
timber that Comcast faults as rotted.

A.

Comcast contends that Dr. McClave‘s model cannot
isolate damages for individual theories of harm, and that it
therefore cannot distinguish between lawful and unlawful
competition. Comcast cites Coleman Motor Co. v. Chrysler
Corp., 525 F.2d 1338, 1353 (3d Cir. 1975), and Concord Boat
Corp. v. Brunswick Corp., 207 F.3d 1039, 1057 (8th Cir.
2000). In both cases, following adverse jury verdicts, the
courts held that the experts‘ theories of damages were
―speculation‖—not ―just and reasonable inferences‖—
because the models did not distinguish between the effects of
lawful and unlawful competition. In Coleman, we quoted the
guidepost of Story Parchment: ―The rule which precludes the
recovery of uncertain damages applies to such as are not the
certain result of the wrong, not to those damages which are
definitely attributable to the wrong and only uncertain in
respect of their amount.‖ Coleman, 525 F.2d at 1353 (quoting
Story Parchment, 282 U.S. at 562).

We are not persuaded by Comcast‘s argument. To
measure damages, Dr. McClave used screens to select and

when class certification was granted and trial so as to comply
with Daubert.

48
average benchmark counties against which to compare the
actual Philadelphia market. The screens themselves were not
intended to calculate damages, but instead to construct an
estimated competitive ―but-for‖ Philadelphia market (a
market absent the alleged anticompetitive conduct). For
example, although the screens incorporated Direct Broadcast
Satellite penetration rates, those rates were included to
estimate typical competitive market conditions, not to
calculate liability for the foreclosure of DBS competitors.14
The model then calculates damages by comparing actual
prices to the constructed ―but-for‖ market. Differences
between actual prices and ―but-for‖ prices reflect
anticompetitive impact. In other words, the model calculates
supra-competitive prices regardless of the type of
anticompetitive conduct. Further, the model uses standard
econometric methodology to calculate damages. See
generally Areeda et al., supra, ¶ 394 (detailing the basic steps
in calculating antitrust damages). Indeed, as Dr. McClave
highlighted, Comcast‘s expert Dr. Chipty employed the same
methodological approach—identify a suitable benchmark and
employ multiple regression analysis to control for
differences—to estimate damages on a class-wide basis. App.
04041 (―Dr. Chipty and I agree that the application of

14
The Concurrence-Dissent misreads this observation as
addressing the on-the-merits validity of the DBS screen. Slip
Concurring-Dissenting Op. at 25-27. We address Comcast‘s
contention regarding the merits of the DBS screen, however,
infra Part X. This observation indicates simply that the
exclusion of the DBS foreclosure theory of liability does not
render Dr. McClave‘s damages methodology incapable of
calculating damages on a class-wide basis if the class can
prove that Comcast engaged in anticompetitive behavior.

49
multiple regression analysis to compare Philadelphia to a
suitable benchmark is an appropriate methodology that can be
applied on a classwide basis to quantify the amount of
economic damages in this case.‖).

As a result, if the class proves at trial that Comcast
engaged in anticompetitive behavior, it can use the
constructed ―but-for‖ market to measure the anticompetitive
impact on the class members. At the class certification stage
we do not require that Plaintiffs tie each theory of antitrust
impact to an exact calculation of damages, but instead that
they assure us that if they can prove antitrust impact, the
resulting damages are capable of measurement and will not
require labyrinthine individual calculations. Cf. Newton, 259
F.3d at 187. We are satisfied that Plaintiffs‘ damages model
meets this burden.15

15
The Concurrence-Dissent states that Dr. McClave‘s
damages theory can establish damages only in the five
counties where RCN attempted to overbuild. This concern
misses the central theory of Plaintiffs‘ case: by deterring the
entry of overbuilders through clustering, Comcast allegedly
maintained higher prices across the entire market area. Dr.
McClave‘s damages model appropriately reflected a ―but-for‖
world by accounting for overbuilding only in the five counties
where RCN attempted to overbuild, and his resulting
calculations showed that—taking the limited actual
overbuilding into account—―the Philadelphia DMA market
prices were elevated above the but-for prices in every county-
year combination.‖ App. 03412. Additionally, the
Concurrence-Dissent apparently takes up the mantle of an
additional Comcast expert and raises multiple arguments
against Dr. McClave‘s damages model not addressed by

50
 Additionally, the cases that Comcast offers are
distinguishable on multiple grounds. Most to the point, those
cases considered the merits of experts‘ theories following
adverse jury verdicts; here, we address only whether Plaintiffs
have provided a method to measure and quantify damages on
a class-wide basis. We have not reached the stage of
determining on the merits whether the methodology is a just
and reasonable inference or speculative. And, to the extent
Comcast worries about distinguishing between lawful and
unlawful conduct, Dr. McClave‘s damages methodology does
not suffer from the defects present in those cases because it
constructs a competitive ―but-for‖ world that includes lawful
competition, not a hypothetical one bereft of both lawful and
unlawful competition. See Concord, 207 F.3d at 1056-1057
(model was ―mere speculation‖ because it ignored
inconvenient evidence, failed to account for external market
events, and did not incorporate economic reality of market);
Coleman, 525 F.2d at 1352-1353 (model premised on
hypothetical world without even lawful competition).16

Comcast‘s experts at the District Court level nor advanced by
Comcast on appeal. We must limit our review to the issues
presented by Appellants and Appellees. We are not permitted
to embark on an intellectual adventure of our own.
16
Comcast adds that because overbuilding occurs at the
franchise level, Dr. McClave‘s county-to-county metric
cannot calculate damages if the jury finds that only some (if
any) franchises were impacted. First, Dr. McClave indicated
that franchises within counties often have identical or nearly
identical pricing, which assuages Comcast‘s concern. See
App. 03409. Second, Comcast is attempting again to redefine
the relevant market: inasmuch as Plaintiffs have established

51
 B.

Comcast‘s remaining arguments contest specific parts
of Dr. McClave‘s damages methodology. These contentions
are a renewal of those it made to the District Court, each of
which the Court rejected. For those determinations to be
beyond the Court‘s discretion, Comcast must convince us that
the Court‘s acceptance of the pieces of Dr. McClave‘s
methodology was clearly erroneous.

At the outset, we agree with the class that the heart of
Comcast‘s arguments are attacks on the merits of the
methodology that have no place in the class certification
inquiry. Even if we were to overrule as clearly erroneous the
District Court‘s findings on all four contested pieces of Dr.
McClave‘s methodology—i.e., modify both of Dr. McClave‘s
screens,17 add population density as a variable, and
incorporate Dr. Chipty‘s proposed method for calculating

that the relevant geographic market can be the Philadelphia
DMA, see supra Part IV.A, their damages model passes
muster at this stage of the proceedings.
17
The Concurrence-Dissent—unlike Comcast‘s experts,
Comcast‘s lawyers and the District Court—identifies a ―third
screen.‖ Slip Concurring-Dissenting Op. at 22. Again, this
―screen‖ was not raised by the parties before us and we do not
address it (we doubt additionally that it is a screen: the two
screens were used to select benchmark counties, whereas the
presence of overbuilders was an identification attached to the
already-selected benchmark counties for purposes of
performing a multiple regression analysis, see App. 03412,
03421 (Corrected McClave Decl.)).

52
discounts—only the final amount of estimated damages
would change. See App. 03082 (Hr‘g Ex.) (chart
demonstrating differing damages amounts based on different
model specifications, including Dr. Chipty‘s suggested
specifications); App. 04557 (Dr. McClave Supplemental
Decl.) (damages remain class-wide and substantial even using
Dr. Chipty‘s proposed methodology, after correcting for two
obvious errors). Comcast‘s assertions do not impeach the
District Court‘s ultimate holding that damages are capable of
common proof on a class-wide basis. See Behrend, 264
F.R.D. at 191; see also In re Scrap Metal Antitrust Litig., 527
F.3d 517, 535 (6th Cir. 2008) (―Indeed, we have never
required a precise mathematical calculation of damages
before deeming a class worthy of certification.‖). All of the
cases Comcast proffers examine damages models on their
merits following adverse jury verdicts. For reasons explained
above, these cases do not address the question at the class
certification stage. Because Comcast‘s contentions do not cast
doubt on the District Court‘s holding that Plaintiffs will be
able to measure class-wide damages through a common
methodology, we decline to consider them further. See
Hydrogen Peroxide, 552 F.3d at 317 (describing the Supreme
Court‘s rule prohibiting consideration of the merits if not
―necessary‖ for purposes of Rule 23) (citing Eisen, 417 U.S.
at 177).

Plaintiffs have provided a common methodology to
measure and quantify damages on a class-wide basis. The
District Court acted within its discretion in so finding.18

18
The Concurrence-Dissent expresses its additional concern
over using mathematical averages across the Philadelphia
DMA, given the potential variation among the franchise

53
areas. Once again, this concern is notably absent from
Comcast‘s briefing (except as already addressed above
regarding the screens and demographic variables). Nor does
the Concurrence-Dissent grapple with the abuse-of-discretion
standard of review we must apply to the District Court‘s
acceptance of Dr. McClave‘s damages model. We also note in
passing that the Concurrence-Dissent overstates the degree of
dissimilarity among the franchise areas. It recognizes that Dr.
McClave‘s model examines actual prices on a county-by-
county level, see Slip Concurring-Dissenting Op. at 39-40
n.36, but fails to note, as Dr. McClave explained: ―Many
franchises within counties often have identical or nearly
identical pricing. More price variability, and thus from an
econometric perspective more information about prices and
their determinants, is obtained by aggregating prices at the
county level.‖ App. 03409 (Corrected McClave Decl.). Not
even Comcast‘s expert contested this reasoning. See App.
03831 (Chipty Decl.); App. 03954 (Chipty Rebuttal Report).
Finally, to the extent the Concurrence-Dissent questions the
appropriateness of using county-level statistics to measure
damages across the entire Philadelphia DMA, we observe that
this question was contested strenuously and repeatedly by the
experts on both sides at the District Court level. See App.
03410 (Corrected McClave Decl.) (explaining choice of
market share screen); App. 03833 (Chipty Decl.) (contesting
market share screen); App. 04066 (McClave Rebuttal Decl.)
(defending market share screen); App. 03961 (Chipty
Rebuttal Report) (disputing screen again); App. 04262
(McClave Reply Decl.) (responding to Dr. Chipty‘s criticisms
of screen). After reviewing the reports and hearing careful
examination of the experts on this point, the District Court
found that Dr. McClave‘s 40% county-level market-share

54
 XI.

The District Court certified the class for resolution of
four claims. Comcast contends that the District Court erred by
certifying the following claim:

Whether Defendants conspired with
competitors, and whether Defendants entered
into and implemented agreements with
competitors, to allocate markets, territories, and
customers for cable television services; and
whether such conduct is a per se violation, or
whether it constitutes a restraint of trade in
violation of Section 1 of the Sherman Act, 15
U.S.C. § 1.

App. 00031 (emphasis added). According to Comcast, the
District Court lacked any legal authority to certify a per se
claim based on the class‘s allegations.

screen was ―supported by the evidence‖ and that Dr. Chipty‘s
rebuttal was not supported by appropriate data. 264 F.R.D. at
184. Through a clearly erroneous lens, we may not reverse a
District Court‘s factual finding if we would weigh the
evidence differently; instead, the Court‘s finding must be
implausible in light of the record, Anderson, 470 U.S. at 573-
574, or completely devoid of minimum evidentiary support
displaying some hue of credibility, Krasnov, 465 F.2d at
1302. The Concurrence-Dissent breezes past this formidable
standard of review to reach its own factual finding.

55
 This is a merits issue beyond the scope of our Rule
23(f) jurisdiction. Comcast misconstrues the District Court‘s
certification order. The Court certified the class and stated
that one of the questions to be litigated is whether there has
been a per se violation. It did not declare that a per se
violation had occurred. Appeals taken pursuant to Rule 23(f)
do not furnish the proper vehicle to address the merits of
Plaintiffs‘ antitrust claims. See McKowan Lowe & Co. v.
Jasmine, Ltd., 295 F.3d 380, 390 (3d Cir. 2002) (describing
the ―scrupulous‖ limits of Rule 23(f) jurisdiction). Comcast
appeals from the District Court‘s determination that questions
of law or fact common to class members predominate, which
was the only issue before the District Court. See App. 00029
(District Ct. Certification Order) (―The only class certification
element that remained in dispute was the requirement of Fed.
R. Civ. P. 23(b)(2) that common issues of law and fact
predominate.‖). Comcast itself stipulated as much. See App.
00436 (Comcast Letter to the District Ct., Mar. 25, 2009)
(―With respect to the issues to be addressed in a new class
certification motion, Comcast is prepared to stipulate that the
only issues to be resolved are those of antitrust impact and
methodology of damages . . . .‖). Comcast‘s request to have
us declare on the merits that Plaintiffs cannot establish a per
se antitrust violation is beyond the scope of the certification
decision from which Comcast appeals pursuant to Rule 23(f).
Accordingly, we do not reach this contention.

*****

We have considered carefully all the contentions
presented by the parties. Plaintiffs have demonstrated that this
case can proceed as a class action. Comcast has not carried its
burden to convince us otherwise. Accordingly, we will

56
AFFIRM in all respects the District Court‘s Order certifying
the class.

57
Behrend, et al. v. Comcast Corporation, et al.,
No. 10-2865

JORDAN, Circuit Judge, concurring in the judgment part and
dissenting in part

I agree with the Majority‟s conclusion, though not its
reasoning, with respect to the question of antitrust impact, and
I therefore join in holding that the District Court did not abuse
its discretion when it determined that Plaintiffs could
establish antitrust impact through evidence common to a class
comprising Comcast cable television customers in the
Philadelphia DMA.1 But because I conclude that damages
cannot be proven using evidence common to that entire class,
I would vacate the certification order to the extent it provides
for a single class as to proof of damages, and I would remand
the case to the District Court to consider whether the class can
be divided into subclasses for the purpose of proving
damages. I therefore respectfully dissent in part.2

1
I adopt the defined terms, such as “DMA,” as used in
the Majority opinion.
2
Although the Majority opinion decides the question
of certification for a single class comprising Comcast
customers in the Philadelphia DMA, it should be noted that
its decision will become a template for resolving similar class
certification questions pending in cases involving the Chicago
and Boston media markets (see Slip Op. at 10 & n.5), and in
all likelihood it will be cited in other lawsuits against cable
television service providers (cf. App. at 3652 (Williams Dec.)
(explaining that, as part of Comcast‟s swaps and acquisitions,
“Adelphia received Comcast‟s cable systems and subscribers

1
 As the Majority explains, Plaintiffs‟ claims have three
elements, (1) an antitrust violation, (2) antitrust impact, and
(3) damages (see Slip Op. at 17 (citing In re Hydrogen
Peroxide Antitrust Litig., 552 F.3d 305, 311 (3d Cir. 2008)).3
In pursuing its motion to decertify the initial class, however,
Comcast effectively conceded that there was predominance
with respect to the element of an antitrust violation,
stipulating that it was contesting only “the Rule 23(b) issues
of predominance of the common issues of (1) antitrust impact
and (2) methodology of damages.” (App. at 438.) When the

located in Palm Beach, Florida and Los Angeles,
California”)). Thus, the problems in the Majority‟s reasoning
will have practical repercussions far beyond this case. I
therefore write not only because I cannot join the Majority in
permitting Plaintiffs to pursue damages on a class-wide basis,
but also to provide a counterpoint to the Majority‟s analysis
for future consideration.
3
Plaintiffs make separate claims for violation of both §
1 and § 2 of the Sherman Act, but each of those claims
contains the three elements described above, with only the
nature of the particular antitrust violation differing. Compare
Hydrogen Peroxide, 552 F.3d at 311 (listing the elements of a
§ 1 claim as “(1) a violation of the antitrust laws – here, § 1 of
the Sherman Act, (2) individual injury resulting from that
violation, and (3) measurable damages”), with Am. Bearing
Co. v. Litton Indus., 729 F.2d 943, 948 (3d Cir. 1984) (listing
the elements of a § 2 claim as “(1) an antitrust violation, in
this case a violation of section 2 of the Sherman Act; (2) fact
of damage or injury; and (3) measurable damages”).

2
District Court granted Comcast‟s motion,4 it accepted that
stipulation and instructed the parties that, moving forward,
they “need only address these discrete issues.” (Id.) On
appeal, after the District Court once more certified a class,
Comcast has again limited its arguments to addressing
predominance as to impact and damages. We are therefore
faced with two related questions: First, whether the District
Court abused its discretion by holding that, as required by
Federal Rule of Civil Procedure 23(b)(3), common issues of
law or fact predominate with respect to the question of
antitrust impact, and, second, whether the District Court
abused its discretion by likewise holding that common issues
of law or fact predominate with respect to the question of
damages.5

4
Because Comcast had moved to decertify the class
entirely before stipulating to all issues other than the
predominance questions described above, the District Court,
which construed the motion to decertify as a motion for
reconsideration, granted the motion only with respect to those
predominance issues and denied it with respect to all other
issues. (App. at 437.)
5
While not expressed, the requirement that there must
be predominance with respect to both antitrust impact and
damages appears to be accepted by the parties and the
Majority, and I likewise accept that predominance is issue
specific. See, e.g., Hydrogen Peroxide, 552 F.3d 305 at 311
(“We examine the elements of plaintiffs‟ claim through the
prism of Rule 23,” to determine whether “proof of the
essential elements of the cause of action requires individual
treatment.” (internal quotation marks omitted)); Newton v.
Merrill Lynch, Pierce, Fenner & Smith, Inc., 259 F.3d 154,

3
 The Majority opinion skillfully lays out the legal
requirements for predominance and the standard under which
we must review the District Court‟s decision, and there is no
need to repeat that legal background. I emphasize, however,
the instruction from Hydrogen Peroxide that the question of
predominance hinges on whether the elements of a class
claim are “capable of proof at trial through evidence that is
common to the class rather than individual to its members.”
552 F.3d at 311-12. With that requirement in mind, I address
the contested elements in turn.

172 (3d Cir. 2001) (“To determine whether the claims alleged
by the putative class meet the requirements for class
certification, we must first examine the underlying cause of
action … . If proof of the essential elements of the cause of
action requires individual treatment, then class certification is
unsuitable.”) Of course, where only some elements of a
claim require individual treatment, while others can be
litigated collectively, it may be appropriate to certify a class
for those elements that can be treated collectively, while
certifying subclasses or requiring individual treatment for
those that cannot. See, e.g., FED. R. CIV. P. 23(b)(4), advisory
committee‟s notes (explaining that application of Rule
23(c)(4)‟s provision allowing “that an action may be
maintained as a class action as to particular issues only” may
be appropriate where, for instance, liability can be proven
class wide, but damages cannot); In re Nassau Cnty. Strip
Search Cases, 461 F.3d 219, 231 (2d Cir. 2006) (remanding
to district court with instructions to certify a class for liability
and to consider whether to also certify for damages or to,
alternatively, certify subclasses for damages).

4
I. Whether Antitrust Impact Can Be Proven Using
Evidence Common To The Class

In seeking class certification, Plaintiffs initially
presented four theories of antitrust impact.6 The District
Court rejected three of them,7 leaving Plaintiffs with only a
single theory of antitrust impact: that Comcast‟s clustering

6
Those theories were: (1) that Comcast‟s high market
share resulting from clustering made it profitable for Comcast
to deny Comcast SportsNet to DBS providers, which lowered
DBS penetration rates and allowed Comcast to raise prices;
(2) that Comcast‟s clustering reduced “benchmark
competition” (the ability of customers to compare service and
prices among competing providers), which allowed Comcast
to raise prices; (3) that Comcast‟s market power increased its
bargaining power vis-à-vis content providers, which allowed
it to raise prices for its services; and (4) that Comcast‟s
clustering deterred competition from overbuilders, allowing
Comcast to raise prices.
7
The District Court rejected the theory that clustering
reduced DBS penetration because it found that Comcast‟s
denial of Comcast SportsNet to DBS providers predated and
was unrelated to clustering. It rejected the theory that
clustering reduced benchmark competition because Plaintiffs
had provided no evidence that television consumers actually
engaged in benchmark competition. It rejected as “wholly
unsupported” the theory that increased bargaining power vis-
à-vis content providers increased prices.

5
reduced overbuilding8 and, therefore, increased prices. Like
the Majority, I see no abuse of discretion in the District
Court‟s holding that antitrust impact may be proven using
evidence that clustering reduced overbuilding and so caused
increased prices. Thus, I agree with my colleagues in the
Majority that the element of antitrust impact is at least
capable of proof on behalf of some class of consumers. The
more complicated question, as I see it, is whether antitrust
impact is capable of proof for a class encompassing all
Comcast customers in the Philadelphia DMA, through the use
of common evidence. 9 On that issue too I agree with the
Majority‟s holding that the District Court was within its
discretion to conclude that the Philadelphia DMA is the

8
“Overbuilding,” as the Majority explained, is where a
second cable provider – the “overbuilder” – “builds and offers
customers a competitive alternative where a
telecommunications company already operates.” (Slip Op. at
9.) The existing provider is often referred to as the
“incumbent” provider.
9
The geographic scope of the class is actually defined
as Comcast‟s Philadelphia cluster, which, as noted by the
Majority, excludes the DMA counties of Lehigh and
Northampton. As Dr. Chipty explains, those are the two
counties in which Comcast has no presence (see App. at 3795
& n.12 (Chipty Reply Dec.)), and, therefore, they would be
excluded from the class regardless of its geographic scope.
For ease of reference, I refer to the class as encompassing the
Philadelphia DMA, rather than the Philadelphia Cluster,
recognizing that those DMA counties in which there are no
Comcast customers are not included in the class.

6
appropriate geographic region within which antitrust impact
can be proven with common evidence. I do not agree,
however, with the Majority‟s reasoning in support of that
conclusion.

Much confusion has been caused in this case by the
conflation of two distinct concepts: the antitrust concept of
“relevant geographic market,” which has traditionally been
defined as the smallest area within which a monopolist can
exercise market power,10 and the class action concept of a
“class definition,” which gives the parameters of a set of
plaintiffs as to whom the elements of a claim can be proven
using common evidence.11 Because, in this case, the class

10
For example, the Federal Trade Commission defines
“relevant geographic market” as the region in which a
hypothetical monopolist “would impose at least a [small but
significant nontransitory price increase] on some customers in
that region” without “this price increase [being] defeated by
substitution away from the relevant product or by …
customers in the region travelling outside it to purchase the
relevant product.” FEDERAL TRADE COMMISSION,
HORIZONTAL MERGER GUIDELINES 14-15 (2010). Cf.
PHILLIP E. AREEDA & HERBERT HOVENKAMP,
FUNDAMENTALS OF ANTITRUST LAW § 5-30 (2010) (“[T]he
relevant inquiry” for identifying a geographic market is “how
far [customers] are willing to travel in order to avoid paying
the defendant monopoly prices.”).
11
See In re DVI, Inc. Sec. Litig., 639 F.3d 623, 639
n.22 (3d Cir. 2011) (explaining that, pursuant to Rule
23(c)(1)(B), the class definition describes both “which
individuals and entities are included” and the “claims, issues

7
definition includes a geographic component, the term
“relevant geographic market” has been used equivocally by
the parties, the District Court, and the Majority to describe
both the area affected by antitrust impact and the area within
which potential class members reside – the latter area being
what I will call, for lack of a better term, the “class region.”12
The problem with that equivocal usage is that the relevant
geographic market and the class region are not necessarily
coterminous. Even if we assume that, within the Philadelphia
DMA, there are many distinct geographic markets that are
relevant for antitrust purposes, as Comcast argues, that does
not mean that Plaintiffs cannot prove, by common evidence,

or defenses to be treated on a class basis”). While Rule
23(c)(1)(B) does not expressly state that the class should
include only those for whom the defined claims can be
proven by common evidence, it is apparent that any class
must be defined in a manner consistent with all Rule 23
requirements, including commonality and predominance. Cf.
id. at 639 & n.22 (explaining that the question of whether
there was predominance when it was alleged that some
members of a proposed class “would be unable to
demonstrate loss causation,” was an issue of “which
individuals and entities are included in the putative class …
primarily relevant to class definition”).
12
The class region will not necessarily be the same
with respect to each element of a class‟s claims. In fact, even
in this case, the class region differs with respect to antitrust
impact and damages because, for the reasons I identify infra
Part II(B), antitrust impact can be proven using common
evidence across a wider region than damages can be.

8
that Comcast‟s acts caused antitrust impact within all of them.
As a theoretical matter, class proof can cover multiple
relevant geographic markets, and, indeed, other Courts of
Appeals have so held. See, e.g., In re Sugar Antitrust Litig.,
559 F.2d 481, 483-84 (9th Cir. 1977) (rejecting the argument
that a class could not be certified “where the antitrust claims
involve a variety of geographic and product markets”);
Windham v. Am. Brands Inc., 539 F.2d 1016, 1018 (4th Cir.
1976) (holding that a district court abused its discretion in
refusing to certify an antitrust class that encompassed “11
different geographic markets”).

While the relevant geographic market and the class
region are conceptually distinct,13 the Majority, like the
District Court, initially attempts to identify the class region in
terms of the relevant geographic market. Unlike the District
Court, however, the Majority decides that because “[d]efining
the relevant geographic market … is an issue of the merits,”
the question of the relevant geographic market is “not
properly before us.” (Slip Op. at 20-21.)

The Majority is correct that defining the relevant
geographic market is not a task we need to undertake at this
stage, but that is not because the task takes us into the merits.
It is rather because, regardless of whether there are one or
many relevant geographic markets associated with the

13
That is not to say that a class region and a relevant
geographic market will always be different. An antitrust
violation may often affect people in only a single geographic
market, in which case the relevant geographic market and the
class region would be in essence the same.

9
Philadelphia DMA, the question before us at this juncture is
whether there is some class, in this case defined
geographically, that can be shown, through common
evidence, to have experienced elevated prices as a result of
reduced overbuilding because of Comcast‟s clustering.
Should that region include only those franchise areas
involved in the Cable System Transactions?14 Should it
include only those franchise areas in which RCN was licensed
to overbuild, but did not? Should it encompass the
Philadelphia DMA or some lesser or greater area? The
Majority does not ask those questions, but, instead, after
determining that Plaintiffs can attempt to prove that the
relevant geographic market is the Philadelphia DMA, the
Majority assumes that that also means that the class is
properly defined to cover the Philadelphia DMA and,
therefore, that Plaintiffs can prove by common evidence that
clustering reduced overbuilding and increased prices
throughout the DMA. (See, e.g., Slip Op. at 51-52 n.16
(dismissing Comcast‟s argument that overbuilding should be
analyzed at the franchise level because “Plaintiffs have
established that the relevant geographic market can be the
Philadelphia DMA”).) Fortunately, what the Majority
assumes, namely that the Philadelphia DMA is the

14
The Cable System Transactions are, as described by
the Majority, the transactions through which Comcast
“clustered” its franchise areas by “contract[ing] with
competing cable providers to either acquire them or to „swap‟
cable systems it owned in areas outside the Philadelphia
DMA for cable systems within the Philadelphia DMA.”
(Slip. Op. at 5.)

10
appropriate class region for proving antitrust impact, is
supportable.

A compelling argument could be made that the class
should consist only of those people living in franchise areas
where RCN was licensed to overbuild, because only those
franchise areas that would otherwise have been overbuilt
could have been affected by the elimination of that
overbuilding.15 Because RCN was licensed to overbuild only
five of the eighteen Philadelphia DMA counties (see, e.g.,

15
At least, Plaintiffs have provided no evidence that
persons outside of franchise areas that would otherwise have
been overbuilt can be affected by the elimination of that
overbuilding. Dr. Williams opines that, where some parts of
a franchise area are overbuilt, the overbuilding can affect
prices in other parts of that same franchise area that are not
overbuilt. (App. at 3704-14 (Williams Dec.) (explaining that
where competing cable companies have “alternating franchise
areas,” overbuilding by one company into portions of the
competitor‟s adjacent franchise area can affect prices in the
portion of the overbuilt franchise area “that remain
monopolized”).) As a theoretical matter, it is also plausible
that, when one franchise area has been overbuilt, the threat of
further expansion by that overbuilder could put downward
pressure on prices in nearby franchise areas. If such an effect
is described in the multitude of expert opinions, however, the
parties have not identified it. Moreover, even if there is such
an effect, it would likely be attenuated by distance. It seems
doubtful that overbuilding in, for instance, Bucks County,
Pennsylvania would influence prices in Kent County,
Delaware.

11
App. at 3640 (Williams Dec.); App. at 4284-85 (Singer Reply
Dec.)), that would suggest limiting the class region to those
five counties.16 Nonetheless, both Dr. Williams and Dr.
Singer opined that, had RCN successfully overbuilt the five
counties in which it was already licensed, it would have
continued overbuilding into the remainder of the Philadelphia
DMA. (App. at 4285 (Singer Reply Dec.) (“[H]ad RCN
entered the five counties that it intended to … it is likely that
RCN would have expanded its footprint beyond those five
counties into geographically contiguous areas throughout the
Philadelphia DMA.”); App. at 4306 (Williams Reply Dec.)
(“RCN likely would have continued to pursue its strategy of
building into other areas in the Philadelphia DMA adjacent to
its existing cable infrastructure, beyond the five counties.”).)
The District Court relied on those statements in holding that
Plaintiffs had shown that the anticompetitive effects of
clustering could be proven throughout the Philadelphia DMA.
Behrend v. Comcast Corp., 264 F.R.D. 150, 174-75 (E.D. Pa.
2010). Though one may be skeptical that RCN would have
overbuilt even the five counties in which it was licensed, let
alone the remainder of the Philadelphia DMA, it was not
clearly erroneous for the District Court to accept that the
prospect of overbuilding throughout the DMA was capable of
proof. Consequently, it was not an abuse of discretion for the
District Court to hold that Plaintiffs could show, by common
evidence, the antitrust impact of clustering throughout the

16
Given that the Class‟s whole theory is rooted in the
premise that Comcast‟s clustering deterred overbuilding, it is
no small matter that RCN – the only entity licensed to
overbuild anywhere in the Philadelphia DMA – was licensed
to overbuild in just five of the eighteen counties.

12
Philadelphia DMA. Accordingly, while I do not agree with
the Majority‟s reasoning, I agree that the District Court was
within its discretion in determining that an appropriate class
region for proving antitrust impact is the Philadelphia
DMA.17

17
The Majority responds to my efforts to identify the
class region by stating that I have “misunderst[ood] an
important distinction,” namely that Plaintiffs have identified a
“„class region‟ … of a „Philadelphia cluster‟ which is distinct
from the contested relevant geographic market of the
“„Philadelphia DMA.‟” (Slip Op. at 26 n.8.) I do
acknowledge that distinction. However, that does not speak
to the point because, in spite of that distinction, there remains
an equivocal use of the term “relevant geographic market.”
That equivocation is evidenced by the Majority‟s statement –
in response to Comcast‟s suggestion that franchise areas
might be the appropriate class region for damages – that
“Comcast is attempting to redefine the relevant market:
inasmuch as Plaintiffs have established that the relevant
geographic market can be the Philadelphia DMA … their
damages model passes muster.” (Slip. Op. at 51-52 n.16.)
The Majority also asserts that there is no question
about the class region because Comcast does not dispute the
class region but disputes only the relevant geographic market.
(Slip Op. at 26 n.8) That is not correct. While Comcast does
not use the term “class region,” Comcast and its experts
plainly argue that the scope of the class is too broad, and they
dispute the District Court‟s conclusion that antitrust impact
can be proven by common evidence across the Philadelphia
DMA. (See, e.g, App. at 3923 (Teece Reply Dec.) (“[E]ven if
RCN would have overbuilt all five counties entirely in the

13
but-for world, this would not be sufficient to conclude that the
impact of the challenged conduct would have affected all
Comcast customers in the Philadelphia DMA.”); id. at 3922
(“I have seen no evidence that RCN ever intended to build out
the entire Philadelphia DMA.”); Appellants Br. at 33 (arguing
that Dr. Williams‟s models do not show that clustering
“deterred overbuilding … in a manner affecting all class
members”); id. at 24-25 (noting that RCN was licensed in
only five counties and arguing that Plaintiffs cannot prove
that RCN would have entered the Philadelphia DMA). While
I do not agree with Comcast‟s effort to define the class region
by reference to the relevant geographic market (any more
than I agree with the Majority‟s conflating of those concepts),
to say that Comcast does not dispute the contours of the class
region is not accurate, as the foregoing citations indicate.
However, even if Comcast had not disputed the class
region, it would still be appropriate for us to address it. The
Majority faults me for, in its view, addressing problems not
raised by Comcast, which the Majority asserts are, therefore,
waived. (See, e.g., slip op. at 43-44 n.15 (“[T]he
Concurrence-Dissent … raises multiple arguments … not
addressed by Comcast‟s expert … . We must limit our
review to the issues presented by Appellants and
Appellees.”). But “there can be no waiver … of the Judge‟s
duty to apply the correct legal standard. … This is particularly
true in the class action context, where „the district court acts
as a fiduciary who must serve as a guardian of the rights of
absent class members.‟” In re Cmty. Bank of N. Virginia, 622
F.3d 275, 302 n.20 (3d Cir. 2010) (quoting United States v.
Ali, 508 F.3d 136, 144 n.9 (3d Cir. 2007) and In re General
Motors Corp. Pick-Up Truck Fuel Tank Prods Liab. Litig., 55

14
F.3d 768, 785 (3d Cir. 1995)). Thus, where Comcast has
raised the issues of whether there is predominance with
respect to antitrust impact and damages, we are required to
“apply the correct legal standard,” – which is to determine
whether those elements can, in fact, be proven using evidence
common to the class – even if that requires us “„to conduct
[our] own thorough [R]ule 23[b] inquiry.‟” Id. (quoting
Sitrman v. Exxon Corp., 280 F.3d 554, 563 n.7 (5th Cir.
2002)). By disregarding the problems I have endeavored to
identify, the result is an overly broad class definition and, to
the extent any legitimate claims are proven, a likely dilution
of recovery. Our fiduciary responsibility to absent class
members requires that we ensure compliance with the
provisions of Rule 23, especially those “„designed to protect
absentees by blocking unwarranted or overbroad class
definitions.‟” Id. at 291 (quoting Amchem Prods., Inc. v.
Windsor, 521 U.S. 591, 620 (1997)); cf. Tri-M Group, LLC v.
Sharp, 638 F.3d 406, 416 (3d Cir. 2011) (“[T]he waiver
principle is only a rule of practice and may be relaxed
whenever the public interest or justice so warrants.”).
Moreover, we must be cognizant of “the pivotal status
of class certification in large-scale litigation,” which is “often
the defining moment in class actions (for it may sound the
„death knell‟ of the litigation on the part of plaintiffs, or
create unwarranted pressure to settle nonmeritorious claims
on the part of defendants).” Hydrogen Peroxide, 552 F.3d at
310 (internal quotation marks omitted). Pointing out
analytical problems central to the certification question is no
frolic and detour. It is our obligation.

15
II. Whether Damages Can Be Proven Using Evidence
Common To The Class

I part ways with the Majority entirely, however, when
it comes to class-wide proof of damages. The only evidence
supporting Plaintiffs‟ claim that damages can be proven using
evidence common to the class is the expert opinion of Dr.
McClave. But, as detailed hereafter, Dr. McClave‟s
testimony is incapable of identifying any damages caused by
reduced overbuilding in the Philadelphia DMA.
Consequently, his testimony is irrelevant and should be
inadmissible at trial, pursuant to Federal Rule of Evidence
702 and Daubert v. Merrell Dow Pharmaceuticals, Inc., 509
U.S. 579 (1993), as lacking fit. Thus, it cannot constitute
common evidence of damages.18

18
Although we have never explicitly held that expert
testimony must satisfy Daubert at the class certification stage,
it is implicit in both Supreme Court precedent and our
precedent. In Wal-Mart Stores, Inc. v. Dukes, the Supreme
Court recently expressed its “doubt” about a district court‟s
conclusion that “Daubert did not apply to expert testimony at
the certification stage of class-action proceedings.” 131 S.
Ct. 2541, 2553-54 (2011). In Hydrogen Peroxide, we
explained that “opinion testimony should not be uncritically
accepted as establishing a Rule 23 requirement merely
because the court holds the testimony should not be excluded,
under Daubert or for any other reason.” 552 F.3d at 323.
Inherent in that statement is the conclusion that a court could,
at the class certification stage, exclude expert testimony under
Daubert.

16
 Even without the guidance of Dukes and Hydrogen
Peroxide, simple logic indicates that a court may consider the
admissibility of expert testimony at least when considering
predominance. A court should be hard pressed to conclude
that the elements of a claim are capable of proof through
evidence common to a class if the only evidence proffered
would not be admissible as proof of anything.
I recognize, of course, that in neither the District Court
nor before us did Comcast describe its challenge to
certification as a challenge to the admissibility of Dr.
McClave‟s testimony. Nonetheless, while it did not use the
language of Daubert, the substance of Comcast‟s challenge
was that Dr. McClave‟s damages testimony was irrelevant
and, therefore, did not fit the case. (See, e.g., Appellants‟ Br.
at 37 (“Dr. McClave admitted that his damages model takes
all of the anticompetitive effects of all of the complained-of
conduct as a whole, and therefore cannot isolate damages
attributable to specific conduct or effects.”); id. at 42 (“Dr.
McClave‟s DBS penetration screen is substantively invalid
because it bears no relation to the competitive conditions that
would have prevailed in the Philadelphia region.”); id. at 43
(“Dr. McClave‟s „market share‟ screen is likewise invalid
because it bears no relation to the competitive conditions that
would have prevailed in the Philadelphia region.”). The
Majority protests my invocation of Daubert, but, regardless
of whether we frame the issue as a question of fit under
Daubert or simply ask whether the District Court abused its
discretion by relying on irrelevant evidence, we are
effectively asking the same question. I have chosen the
terminology of Daubert because it is particularly apt for
describing the difficulty created by the change in Plaintiffs‟

17
theory of impact and the consequent disconnect between that
altered theory and Dr. McClave‟s expert report. The short of
it is, Dr. McClave‟s model no longer fits the case. This
observation is not, as the Majority fears, either an invitation
or a demand for mini-trials in conjunction with class
certification motions.
I note here as well my disagreement with the
Majority‟s claim that, at the class certification stage, we need
only “evaluate expert models to determine whether the theory
of proof is plausible.” (Slip Op. at 47 n.13.) The Majority
supports that position by quoting Hydrogen Peroxide’s
statement that “„if such impact is plausible in theory, it is also
susceptible to proof at trial through available evidence
common to the class.‟” (Id. (quoting Hydrogen Peroxide, 552
F.3d at 325).) That quotation is better understood, however,
if one includes the first half of the quoted sentence, which
states that “the question at class certification is whether, if
such impact is plausible in theory, it is also susceptible to
proof at trial through available evidence common to the
class.” 552 F.3d at 325 (emphasis added). Thus, Hydrogen
Peroxide does not suggest that we need only “evaluate expert
models to determine whether the theory of proof is plausible,”
as the Majority claims. To the contrary, Hydrogen Peroxide
instructs that, even where a theory is plausible, “the question
at class certification is whether” that plausible theory is
susceptible to common proof. Id. If the only common proof
offered is inadmissible expert testimony, then Plaintiffs have
not met their burden of showing that the theory – plausible or
not – is capable of common proof.

18
 Our precedent explains that Rule 702 and Daubert
impose three requirements for admission of expert testimony:
the expert must be qualified, the expert‟s methodology must
be reliable, and the expert‟s proffered testimony must fit the
particular case. See United States v. Schiff, 602 F.3d 152, 172
(3d Cir. 2010). Testimony fits when it “„is sufficiently tied to
the facts of the case that it will aid the jury in resolving a
factual dispute.‟” Id. at 173 (quoting United States v.
Downing, 753 F.2d 1224, 1242 (3d Cir. 1985)). Like any
relevancy determination, the question of fit is reviewed for
abuse of discretion. United States v. Ford, 481 F.3d 215,
217-18. Here, Dr. McClave‟s opinion fails the requirement of
“fit” because it is disconnected from Plaintiffs‟ only viable
theory of antitrust impact, i.e., reduced overbuilding, and,
thus, the proffered expert testimony cannot help the jury
determine whether reduced overbuilding caused damages.19
It was, consequently, an abuse of discretion for the District
Court to consider Dr. McClave‟s opinion as demonstrating
that damages could be proven using evidence common to the
class.

As explained by the Majority, Dr. McClave arrived at
his damages calculation by comparing actual cable prices in
the Philadelphia DMA to prices in benchmark counties
outside the Philadelphia DMA. By making those
comparisons, Dr. McClave sought to identify the “but for”
price of cable – that is the price that would have prevailed in
the Philadelphia DMA but for the alleged anticompetitive

19
I need not, and do not, question whether Dr.
McClave is qualified as an expert or whether his methodology
is reliable.

19
conduct of Comcast. (App. at 3407 (McClave Dec.).) For
that comparison to be relevant, however, Dr. McClave‟s
benchmark counties must reflect the conditions that would
have prevailed in the Philadelphia DMA in the absence of any
impact from that conduct. (Cf. App. at 719 (McClave Cross)
(stating that the goal of his bechmarking model was to
identify “counties that reflect characteristics that one would
find absent … the effects of [Comcast‟s alleged
anticompetitive] conduct”).) And because the only surviving
theory of antitrust impact is that clustering reduced
overbuilding, for Dr. McClave‟s comparison to be relevant,
his benchmark counties must reflect the conditions that would
have prevailed in the Philadelphia DMA but for the alleged
reduction in overbuilding. In all respects unrelated to reduced
overbuilding, the benchmark counties should reflect the
actual conditions in the Philadelphia DMA, or else the model
will identify “damages” that are not the result of reduced
overbuilding, or, in other words, that “are not the certain
result of the wrong.” Story Parchment Co. v. Paterson
Parchment Paper Co., 282 U.S. 555, 562 (1931); see also,
e.g., Coleman Motor Co. v. Chrysler Corp., 525 F.2d 1338,
1353 (3d Cir. 1975) (“„The rule which precludes the recovery
of uncertain damages applies to such as are not the certain
result of the wrong.‟” (quoting Story Parchment, 282 U.S. at
562)); Amerinet, Inc. v. Xerox Corp., 972 F.2d 1483, 1494
(8th Cir. 1992) (same); Broan Mfg. Co. v. Associated Distrib.,
Inc., 923 F.2d 1232, 1235 (6th Cir. 1991) (same).

Dr. McClave‟s benchmark counties fail in that regard
because he formulated his model at a time when Plaintiffs had
four separate theories of antitrust impact, and so he did not
select his benchmark counties to isolate the impact of reduced
overbuilding. He chose them, as one would expect, to reflect

20
the impact of other conditions in addition to reduced
overbuilding. Consequently, as described in greater detail
below, once the District Court rejected Plaintiffs‟ other
theories of antitrust impact – leaving only the reduced-
overbuilding theory – Dr. McClave‟s model no longer fits
Plaintiffs‟ sole theory of antitrust impact and, instead,
produces damages calculations that “are not the certain result
of the wrong.” Story Parchment, 282 U.S. at 562.20

A. Dr. McClave’s Benchmark Counties Do Not
Reflect “But For” Conditions in the
Philadelphia DMA

To identify his benchmark counties, Dr. McClave used
three “screens.” First, he screened for counties where
Comcast‟s market share was “less than 40%,” because that
figure identified “markets where Comcast is likely to have
less market power than it has acquired in the Philadelphia
market.” (App. at 3410 (McClave Dec.).) Second, he
screened for counties where DBS penetration21 was “at or
above the national average” because “DBS … penetration

20
Whether Dr. McClave‟s opinion would have fit had
the District Court allowed Plaintiffs to pursue all four of their
theories of antitrust impact is irrelevant at this point.
21
As noted by the Majority, “DBS” stands for “direct
broadcast satellite” television service. (Slip Op. at 27.) Dr.
McClave actually used penetration rates for all alternative
delivery systems (“ADS”), rather than just DBS systems. He
opined, however, and the parties seem to agree, that “ADS is
a proxy for DBS penetration rates.” (App. at 3410.)

21
was allegedly constrained by the anticompetitive behavior of
Comcast.” (Id.) Third, having identified counties in which
Comcast‟s share was less than 40 percent and DBS
penetration was above the national average, Dr. McClave
screened for overbuilding, identifying “each of the
benchmark counties … as either overbuilt or not overbuilt.”
(App. at 3411-12 (McClave Dec.).) While those screens
might, if properly employed, have helped identify relevant
benchmark counties in a case involving antitrust impacts
beyond limited overbuilding, they fail to identify the “but for”
conditions that are relevant to what is now the only impact of
Comcast‟s allegedly anticompetitive conduct, namely the
deterrence of overbuilding. They, therefore, cannot help
identify damages caused by that impact. I examine the
screens in reverse order.

1. The Overbuilt Counties Screen

While there are several problems in Dr. McClave‟s
opinion that reflect the lack of fit, nothing demonstrates it
with more certainty than this: For thirteen of the eighteen
counties in the Philadelphia DMA, Dr. McClave‟s opinion
does not even attempt to show that there were elevated prices
resulting from reduced overbuilding. In fact, he assumes that
there was no such effect.

As noted above, after identifying his benchmark
counties using the market share and DBS penetration screens,
Dr. McClave used a third screen to divide those counties into
two groups, identifying “each of the benchmark counties …

22
as either overbuilt or not overbuilt.”22 (App. at 3411-12
(McClave Dec.).) Having done so, Dr. McClave estimated
“but for” competitive prices, by comparing, on a county by
county basis, prices in the eighteen actual Philadelphia DMA
counties to prices in either the “overbuilt” or “not overbuilt”
benchmark counties, and – crucially – he did so “assum[ing]
that only the five counties that RCN indicated it planned to
enter as an overbuilder would have been overbuilt.” (App. at
3412 (McClave Dec.).) At the outset, therefore, it is clear that
Dr. McClave assumed that elevated prices resulting from

22
The Majority notes that the overbuilding screen is
not mentioned by the parties or the District Court. (Slip Op.
at 52 n.17.) While it is true that the parties do not use the
terminology “overbuilding screen,” the District Court did
indeed describe the concept to which I have given that label.
See Behrend, 264 F.R.D. at 182 (“Once a county qualified as
a benchmark for a particular year by satisfying [the DBS
penetration and market share screens], it was examined to
determine whether or not it had been significantly
overbuilt.”). Whether one uses the “screen” terminology is
not what is important. Dr. McClave, in fact, does not
describe any of the benchmarking criteria as “screens,” which
is a term that appears to have been only later applied to his
methods.
Regardless of the terminology, the fact remains that
Dr. McClave did screen for overbuilding in an attempt to
account for elevated prices resulting from reduced
overbuilding. Thus, that screen cannot be ignored in any
“rigorous analysis,” Hydrogen Peroxide, 552 F.3d at 318, of
whether damages resulting from reduced overbuilding can be
proven by common evidence.

23
reduced overbuilding would be present in only five of the
eighteen Philadelphia counties. Dr. McClave then explained
that, after making his calculations, “the overbuilt factor
indicate[d] lower prices [in his model] in counties where the
overbuilding factor [was] present.” (App. at 3422 (McClave
Dec.) (emphasis added).) Thus, Dr. McClave‟s model
assumes that elevated prices from reduced overbuilding could
be present only in the five counties “that RCN indicated it
planned to enter,” and the model did, in fact, identify elevated
prices from reduced overbuilding only in those counties.
(App. at 3412, 22 (McClave Dec.).) For the remaining
counties, while there may be some uncertainty as to what
exactly caused any elevated prices, this much is certain: the
elevated prices identified by Dr. McClave in those thirteen
counties were, according to Dr. McClave himself, the result
of something other than reduced overbuilding. Consequently,
any “damages” identified by Dr. McClave with respect to
those thirteen counties are “uncertain damages … [that] are
not the certain result of [reduced overbuilding],” and “may be
substantially attributable to lawful competition.” Coleman
Motor, 525 F.2d at 1353 (quoting Story Parchment, 282 U.S.
at 562).

Because Plaintiffs have been limited by the District
Court to an overbuilding theory of antitrust impact, any price
elevation resulting from a source other than reduced
overbuilding is simply irrelevant. Thus, not only have
Plaintiffs failed to show that damages can be proven using
evidence common to the class, they have failed to show, for
thirteen counties in the Philadelphia DMA, that damages can
be proven using any evidence whatsoever – common or
otherwise. Perhaps, in those other counties, there is a way to
show damages resulting from reduced overbuilding, but, if so,

24
Plaintiffs have not identified it. As the burden lies with
Plaintiffs to establish predominance, that alone should compel
us to vacate the District Court‟s certification order with
respect to class-wide proof of damages.23

2. The DBS Penetration Screen

Dr. McClave screened for counties where DBS
penetration was at or above the national average because
“DBS … penetration was allegedly constrained by the

23
The Majority states that, in criticizing Dr.
McClave‟s model for identifying overbuilding damages in
only five counties, I have “misse[d] the central theory of
Plaintiffs‟ case: by deterring the entry of overbuilders through
clustering, Comcast allegedly maintained higher prices across
the entire market area.” (Slip Op. at 50-51 n.15.) This
misperceives my reasoning. I understand Plaintiffs‟ theory
but have pointed out that the theory, as altered by the District
Court‟s ruling, no longer matches Dr. McClave‟s opinion.
More precisely, Plaintiffs‟ claim is that by reducing
overbuilding “Comcast allegedly maintained higher prices
across the entire market area,” (id.) whereas Dr. McClave
attempts to show that, by reducing overbuilding, Comcast
maintained higher prices in only the “five counties that RCN
indicated it planned to enter as an overbuilder,” (App. at 3412
(McClave Dec.)). The Majority notes that this particular
problem with Dr. McClave‟s damages theory was not
identified by Comcast, but we ought note overlook significant
problems with the class certification simply because they are
ones we have identified rather than ones to which our
attention has been directed.

25
anticompetitive behavior of Comcast.” (App. at 3410
(McClave Dec.).) Using that screen would have been
appropriate if, as Plaintiffs originally argued and as Dr.
McClave was originally informed, DBS penetration had been
constrained by Comcast‟s anticompetitive conduct. But, as
the District Court explicitly held, Plaintiffs failed to tie
“Comcast‟s clustering activity in the Philadelphia DMA to
reduced DBS penetration.” Behrend, 264 F.R.D. at 165.
Consequently, there is no evidence in the record suggesting
that DBS penetration in the Philadelphia DMA was in any
way affected by Comcast‟s allegedly anticompetitive conduct.
Rather, the District Court found that, while DBS penetration
in Philadelphia was well below the national average, the
cause of that reduced penetration – Comcast‟s refusal to
distribute Comcast SportsNet through DBS providers –
“occurred prior to the class period,” is “unrelated to
clustering,” is “based upon valid business considerations” and
is “specifically permitted” by the FCC. Id.

Therefore, while DBS penetration in the Philadelphia
DMA is below the national average, the cause of that reduced
rate predated and is unrelated to Comcast‟s clustering and,
thus, even in the absence of Comcast‟s allegedly
anticompetitive conduct, DBS penetration in the Philadelphia
DMA would be no different than the below average rate that
has actually prevailed. As a result, any benchmark county
used to identify “but for” conditions should use the actual
DBS penetration rate from the Philadelphia DMA. Dr.
McClave, nonetheless, used the much higher national average

26
rate,24 which identified benchmark counties in which cable
prices were lower than in counties having DBS penetration
similar to that in the Philadelphia DMA.25 Because Dr.
McClave then calculated damages by comparing prices in
those benchmark counties (with national average DBS
penetration and, therefore, lower prices) to actual prices in the
Philadelphia counties (with below national average DBS
penetration and, therefore, higher prices), at least a portion of
Dr. McClave‟s damages calculation results from the
Philadelphia DMA having below national average DBS
penetration. Since the cause of the below national average
DBS penetration in the Philadelphia DMA is “unrelated to
clustering,” is “based upon valid business considerations,”
and is “specifically permitted” by the FCC, id., that reduced
DBS penetration is the result of lawful competition, and, it
follows, “[t]he damage figures advanced by [Dr. McClave]
may be substantially attributable to lawful competition.”
Coleman Motor, 525 F.2d at 1353.

The Majority responds to this flaw only by stating that
the DBS penetration screen was “included to estimate typical
competitive market conditions, not to calculate liability for

24
According to Dr. McClave, national average DBS
penetration during the six year period for which he calculated
damages averaged 24.17%, whereas actual DBS penetration
in the Philadelphia DMA averaged 12.77%. (App. at 3411
(McClave Dec.).)
25
The District Court discussed extensively the
evidence that “DBS competition constrains cable prices.”
Behrend, 264 F.R.D. at 163-65.

27
the foreclosure of DBS competitors.” (Slip Op. at 49.) That
explanation misses the mark. In identifying benchmark
counties for use in a damages analysis, the goal is not to
identify “typical competitive market conditions.” The goal is,
and must be, to identify the conditions that would have
existed “but for” Comcast‟s alleged anticompetitive conduct.
In this case, even in the “but for” hypothetical world, the
Philadelphia DMA would not have been typically
competitive. Rather, given the District Court‟s findings, there
is no question that, as a result of Comcast‟s lawful
competition, DBS penetration in the Philadelphia DMA
would have been well below that present in a typical
competitive market. Thus, by comparing Philadelphia to
benchmark counties having the much higher national average
DBS penetration, Dr. McClave‟s model wrongly “calculate[s]
liability for the foreclosure of DBS competitors,” (id.)
imposing damages based on the prices that would have
prevailed had Comcast not lawfully foreclosed DBS
competition.

3. The Market Share Screen

Dr. McClave screened for counties where Comcast‟s
market share was “less than 40%,” because that figure
represented the midpoint between Comcast‟s 20 percent share
before the class period and its 60 percent share during the
class period and so identified “markets where Comcast is
likely to have less market power than it has acquired in the
Philadelphia market.” (App. at 3410 (McClave Dec.).)
Under Plaintiffs last viable theory of antitrust impact,
however, while Comcast‟s market share is relevant to the
question of whether there has been any reduction in
overbuilding, it is not relevant – at least not in isolation – to

28
determining the damages caused by that reduction. Instead,
the relevant market share is the share that would have been
held by any incumbent in the “but for” hypothetical world.

As an illustration of that point, consider a hypothetical
county with two equally sized franchise areas. Assume that,
prior to the class period, Comcast had a 100 percent share of
one franchise area and that AT&T had a 100 percent share of
the other, so that each had a 50 percent share of the county as
a whole. Assume further that, as part of its clustering efforts,
Comcast acquired AT&T‟s franchise area so that, today,
Comcast has a 100 percent share of the entire county. To test
the theory that clustering reduces overbuilding, a comparison
between Comcast‟s current 100 percent share of the county
and the 50 percent share that Comcast would have had but for
its clustering would surely be relevant in determining whether
clustering effected any reduction in overbuilding.

Next, assume that, after making that comparison,
Plaintiffs could show that, had no clustering taken place,
RCN would have overbuilt 20 percent of each of the two
franchise areas, so that, in the “but for” world, RCN would
have a 20 percent share in each franchise area, and Comcast
and AT&T would each have an 80 percent share in their
respective franchise area. Pursuant to Plaintiffs‟ only theory
– that increased overbuilding decreases prices – any damages
in that scenario arise solely from the difference between
RCN‟s 20 percent share in the “but for” franchise areas and
RCN‟s zero percent shares in the current franchise areas. The
damages resulting from that foregone overbuilding are the
same whether, in the “but for” world, the remaining 80
percent of the franchise in question would have been
controlled by Comcast or by AT&T. It follows, therefore,

29
that once the antitrust impact of Comcast‟s clustering – i.e.,
the reduction in overbuilding – has been identified and
accounted for as part of an overbuilding screen, any market
share screen applied to isolate the “but for” conditions that
would have prevailed in the Philadelphia DMA should screen
not just for Comcast‟s share, but for the share of whatever
incumbent would have been present but for the clustering. 26

26
Again, this is not to say that Comcast‟s market
share, in particular, will never be relevant. As just discussed,
it is highly relevant for determining antitrust impact.
Moreover, it might have been relevant to damages had the
District Court not excluded three of Plaintiffs‟ theories of
antitrust impact. In fact, the market share screen appears to
be another relic of the Plaintiffs‟ having initially presented
four theories of impact. One of those theories was that
Comcast‟s increased market share increased its bargaining
power and allowed it to reduce prices, Behrend, 264 F.R.D. at
178-81, and a second was that Comcast‟s increased market
share reduced the ability of consumers to engage in
benchmark pricing by comparing Comcast‟s prices to the
prices of other cable providers in the region, id. at 175-78.
Had either of those theories survived the class certification
process, it might have made sense for Dr. McClave to screen
for Comcast‟s market share, because, under those theories,
Comcast‟s market share directly impacted price. But the
District Court rejected those theories, allowing Comcast to
proceed only on a theory that clustering reduced overbuilding.
Under that theory, what is relevant is the market share of all
incumbent cable providers vis-a-vis overbuilders.

30
 Because Dr. McClave‟s model already assumes that
there has been a reduction in overbuilding and screens for it,
the relevant market share for damages purposes is the share of
the market maintained by any incumbent – regardless of the
identity of the particular incumbent. By calculating the
appropriate market share screen using only Comcast‟s
average share throughout the Philadelphia DMA, Dr.
McClave has ignored any market share that, in the “but for”
hypothetical world, would have been maintained by an
incumbent other than Comcast. For franchise areas where
Comcast was not present prior to the class period, Dr.
McClave should have calculated damages by comparing
Comcast‟s current share to the “but for” share that would
have been held by any incumbents Comcast replaced.
Because he instead effectively calculated damages by
comparing Comcast‟s current share to Comcast‟s zero percent
share prior to the class period,27 he unfairly suppressed the
relevant incumbent share and artificially inflated the damages
calculation.

27
I say he “effectively calculated damages” that way
because Dr. McClave did not actually make a franchise by
franchise comparison, which, as discussed infra Part II(B), is
itself problematic. He instead calculated Comcast‟s market
share by averaging its share throughout the Philadelphia
DMA. But, because he included in that average Comcast‟s
zero percent share in the franchises in which it had not been
present prior to the class period, instead of including the share
held by the incumbent Comcast replaced, it is fair to say that
he effectively calculated damages by comparing Comcast‟s
actual share in those franchise areas to Comcast‟s zero
percent share prior to the class period.

31
 Because none of Dr. McClave‟s screens reflect the
conditions that would have prevailed in the Philadelphia
DMA “but for” any reduction in overbuilding, the damages
Dr. McClave calculated are “not the certain result of the
wrong,” Story Parchment, 282 U.S. at 562. Accordingly, Dr.
McClave‟s opinion cannot help a jury determine damages,
and so would be inadmissible at trial for lacking fit. Because
Dr. McClave‟s opinion is the only evidence Plaintiffs have
offered to meet their burden of showing that damages can be
proven using evidence common to the class, I would vacate
the District Court‟s class certification with respect to class-
wide proof of damages.28

28
The Majority suggests that any problems with Dr.
McClave‟s screens are “attacks on the merits of the
methodology that have no place in the class certification
inquiry,” because, “[e]ven if we were to overrule as clearly
erroneous the District Court‟s findings on all four contested
pieces of Dr. McClave‟s methodology – i.e., modify both of
Dr. McClave‟s screens … only the final amount of estimated
damages would change.” (Slip Op. at 52.) I disagree. First,
the problems I have identified with Dr. McClave‟s screens
call into question not only the amount of damages but also
whether there are any means of proving damages at all in
thirteen of the eighteen Philadelphia DMA counties. See
supra Part II(A)(1). Second, if Dr. McClave‟s model does
not presently constitute a relevant means of calculating class-
wide damages, to say that the model might be fixed, for
example by “modify[ing] both of Dr. McClave‟s screens,”
(Slip Op. at 52), is no better than saying that Plaintiffs have
made “a threshold showing” of predominance or shown a
sufficient “intention to try the case in a manner that satisfies

32
 B. Damages Are Not Capable of Being Proven
By Evidence Common to the Entire Class

While my thoughts thus far have focused on why
Plaintiffs have not met their burden of showing that damages
can be proven using evidence common to the class, none of
the problems I have noted are necessarily irreparable. That is,
Dr. McClave could conceivably redesign his model to address
overbuilding throughout the Philadelphia DMA, to use actual
DBS penetration rates, and to screen for the market share of
all incumbents, not just Comcast. Nevertheless, there remains
an intractable problem with any model purporting to calculate
damages for all class members collectively.

Central to Dr. McClave‟s damages model is the
conclusion that the price of cable television service in any
given franchise area is affected by the relative market shares
of at least three entities: overbuilders, DBS providers, and
incumbent cable providers. All else being equal, for example,

the predominance requirement” – both of which are
insufficient under Hydrogen Peroxide. 552 F.3d at 321
(internal quotation marks omitted). Plaintiffs have the burden
of establishing predominance and, until they have actually
proffered a model that shows how damages can be calculated
on a class-wide basis, they have not met that burden –
particularly when the only evidence they have offered should
be entirely inadmissible. The Majority‟s willingness to
overlook the debilitating flaws in Dr. McClave‟s model in an
effort to avoid an “attack on the merits,” is precisely the kind
talismanic invocation of “concern for merits-avoidance” that
Hydrogen Peroxide forbids. Id. at 317 n.17.

33
areas that are overbuilt will have lower prices than areas that
are not overbuilt, and areas with high DBS penetration will
have lower prices than areas with low DBS penetration. For
that reason, Dr. McClave‟s model identifies benchmark
counties by screening for the relative market shares of those
three entities.29 While I do not accept the manner in which
Dr. McClave has measured the relative shares of those
entities in the “but for” Philadelphia DMA, I accept the
premise that the relative shares have significant influence on
the price of cable television service.

If price does vary with the changes in relative share
within a franchise area, however, it is hard to see how those
650 franchise areas30 can simply be treated as average for
purposes of proving damages. The record indicates that, on
the contrary, the “but for” market shares of overbuilders, DBS
providers, and incumbent providers would vary, sometimes
significantly, from franchise area to franchise area.

Addressing overbuilding first, RCN – the only party
licensed to overbuild any part of the Philadelphia DMA – was
licensed to overbuild in only five counties. (App. at 3640
(Williams Dec.); App. at 4284-85 (Singer Reply Dec.).)

29
Or, at least, he screens for overbuilders, DBS
providers, and a single incumbent provider – Comcast. I have
already identified, supra Part II(A)(3), why he should instead
screen for incumbent share.
30
Dr. Besen, one of Comcast‟s experts, reports that
there are 649 unique franchise areas in the Philadelphia
DMA. (App. at 3782 (Besen Reply Dec.).)

34
While Plaintiffs‟ experts have opined that, had RCN
successfully overbuilt those five counties, it would have
continued overbuilding elsewhere, (App. at 4284-85 (Singer
Reply Dec.)), any overbuilding into the other parts of the
Philadelphia DMA would, it seems clear, have come later
than the overbuilding of the five licensed counties. Thus,
while some franchise areas might have been overbuilt early in
the class period, other franchise areas would likely never have
been overbuilt at all or have been overbuilt only later in the
class period. There might, for instance, in the “but for” world
be some franchise areas that were 50 percent overbuilt for the
entire class period and other franchise areas that were only 5
percent overbuilt and only for a single year, or perhaps not
overbuilt at all. That means that, both throughout the
Philadelphia DMA and throughout the class period, there
would probably be very significant variation in the “but for”
level of overbuilding from franchise area to franchise area.

Consider next DBS penetration. Dr. McClave testified
that the DBS penetration rate he used for the Philadelphia
DMA was an average for the DMA, but he also said that it
was his understanding that “DBS penetration varies across the
cluster here” and that it was “possible that some of the
counties in the Philadelphia DMA in fact have penetration
that‟s above the national median.” (App. at 729-30 (McClave
Cross).) Thus, according to Dr. McClave, not only does DBS
penetration vary across the Philadelphia DMA, but the
variation is pronounced enough that some parts of the
Philadelphia DMA have above national average DBS
penetration despite the fact that the Philadelphia DMA, as a
whole, has DBS penetration at only half the national average.
Because DBS penetration was unaffected by Comcast‟s
alleged anti-competitive conduct, see supra Part II(A)(2),

35
DBS penetration in the “but for” Philadelphia DMA would
likewise vary significantly from one franchise area to another.

Finally, with respect to the incumbents‟ market share,
the record gives little information regarding what the share of
any non-Comcast incumbent would be in the “but for” world.
We do know, though, that Comcast‟s share prior to clustering
varied markedly from franchise area to franchise area. (See,
e.g., App. at 3833 (Chipty Dec.) (stating that Comcast “had a
zero percent share of housing units in the majority of
counties” and, therefore, that “Comcast‟s share in the
counties in which it was present was substantially higher than
[its average market share]”); App. at 733 (McClave Cross)
(testifying that, at the beginning of the class period, Comcast
was present in “maybe half, maybe less of the counties” and
that its share “in the counties where [it was] present” was
probably higher than its average share)). And, where the
other two components of market share – DBS penetration and
overbuilding31 – vary from one franchise area to another, it
becomes a near mathematical certainty that the remaining
portion of the franchise held by incumbent cable providers
must likewise vary.32

31
While there may be other “alternative delivery
systems” that have a limited share of the market, Dr.
McClave includes those providers in his DBS penetration
screen, see supra note 21, and they are, therefore, accounted
for.
32
It is possible, of course, that the variation in DBS
and overbuilder shares could be such that the combined total
of the two is the same in different franchise areas, and,
therefore, it is not a true mathematical certainty that

36
 The wide variation in the relative market shares
evidenced by the record makes it hard to imagine a means of
calculating class-wide damages. Even if Dr. McClave‟s
benchmarks were not problematic, to say that Comcast‟s “but
for” share of the market throughout the Philadelphia DMA
would be, on average, 40% is about as meaningful as saying
that “with one foot on fire and the other on ice, I am, on
average, comfortable.”33 Given that the three major factors
identified as influencing price – overbuilding, DBS
penetration, and incumbent share – vary widely within the
franchise areas across the DMA, and given further that
Comcast prices its cable service at the franchise level, (see
App. at 716), I have difficulty accepting that it is appropriate
to ignore those differences and take an average across the
counties of the DMA.34

incumbent share must also vary. That that would occur
across the 650 franchise areas, however, seems implausible in
the extreme.
33
Sometimes attributed to Mark Twain, the actual
source of this quote is unknown.
34
The Majority asserts that “concern over using
mathematical averages across the Philadelphia DMA … is
notably absent from Comcast‟s briefing ….” (Slip Op. at 53-
54 n.18.) But it is not absent. In fact, Comcast criticizes Dr.
McClave‟s screens by explaining that:

prior to the Transactions[,] Comcast did not
operate in the majority of franchise areas in the
DMA. By contrast, in the franchise areas where
Comcast did operate, it is undisputed that

37
 This primary flaw in Dr. McClave‟s methodology –
using a single set of assumptions for the entire Philadelphia
DMA – cannot be fixed merely by altering his model. It
seems to me that no model can calculate class-wide damages
because any damages – such as they may be – are not
distributed on anything like a similar basis throughout the
DMA.35 Rather, where some class members might reside in a

Comcast‟s market share was significantly
higher than 40%. Thus, the pre-class “20%”
market share Dr. McClave employed in the
creation of his screen is a mirage, arrived at
solely through the artifice of averaging
Comcast‟s greater-than-40% share of markets
where it did operate with its “0% share” in
hundreds of markets where it was not even
present.

(Appellants Br. at 43.) That criticism precisely mirrors my
own. Because of the significant variation in the market
makeup from franchise area to franchise area, DMA-wide
averages are not reliable. See also infra n.35.
35
This is not simply a case where there might be some
variation in the amount of damages from one class member to
another that can be ignored in order to gain the benefit of
class treatment. Instead, due to the wide variations in the
market makeup of the franchise areas across the DMA,
proving damages will require some factual inquiry into the
relative market shares of overbuilders, DBS providers, and
incumbents in individual franchise areas (or perhaps, as
subsequently noted in this dissent, groups of franchise areas).
The Majority, quoting Wright‟s Federal Practice and

38
franchise area that would have been 50 percent overbuilt for
the entire class period and other class members might reside
in a franchise area that would have been only 5 percent
overbuilt and only for a single year, or not overbuilt at all, it
strains credulity to believe that the damages suffered by those
individuals would all be the same as a result of reduced
overbuilding. Yet Dr. McClave‟s model treats them as
though they are the same,36 as would any model attempting to
calculate damages on an average class-wide basis.

Procedure, suggests that those differences in damages should
not affect the certification process because “„it uniformly has
been held that differences among the members as to the
amount of damages incurred does not mean that a class action
would be inappropriate.‟” (Slip. Op. at 45-46 (quoting
CHARLES ALAN WRIGHT ET AL., FEDERAL PRACTICE AND
PROCEDURE § 1781 (3d ed. 2005)).) I agree with the quoted
statement, but would point also to the following quote from
the same treatise: “Rather, the question of damages can be
severed from that of liability and tried on an individual basis.”
Id. Thus, neither Wright – nor any authority I can find –
suggests that where there are wide differences in damages
from one class member to another, those differences can be
ignored. Wright suggests instead that those differences can
be accounted for by considering liability on a class-wide basis
but damages on a more individualized basis – consistent with
what I propose.
36
I recognize that Dr. McClave‟s model does not treat
all franchise areas exactly the same, because he uses actual
prices on a county-by-county level and, as a result, calculates
a separate “but for” price for each county. (App. at 3424-26
(McClave Dec.).) But, while he uses actual prices on a

39
 The variation in conditions within the nearly 650
franchise areas in the Philadelphia DMA means that the issue
of damages is more fractured than a single class can
accommodate. I do not suggest that there necessarily would
need to be 650 subclasses. It may well be that subclasses
could be created encompassing groups of multiple franchise
areas having similar demographics. See, e.g., Eisen v.
Carlisle & Jacquelin, 391 F.2d 555, 566 (2d Cir. 1968)
(explaining that where “differences among the class members

county-by-county level, he calculates the “but for” prices
using the same benchmark counties for the entire Philadelphia
DMA (again, excepting Lehigh and Northampton, where
Comcast has no presence). He treats the DMA as though the
“but for” conditions would have been the same throughout.
The Majority states that this criticism “overstates the
degree of dissimilarity among the franchise areas” because I
fail to note that “[m]any franchise areas within counties often
have identical or nearly identical pricing.” (Slip Op. at 54
n.18 (quoting App. 3409 (McClave Dec.).) It may well be
that there are similarities allowing for grouping of franchise
areas, as I note in suggesting the possibility of subclasses.
More fundamentally, however, the problem with Dr.
McClave‟s opinion is not that it fails to account for variations
in actual prices in the Philadelphia DMA, but that it fails to
account for variations in the “but for” conditions that would
have existed within the Philadelphia DMA. By so doing, the
model is unable to distinguish between persons living in areas
that may have been highly overbuilt and who, thus, would
have suffered substantial damages, and persons living in areas
that may never have been overbuilt and who, thus, would
have suffered no damages.

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bear only on the computation of damages,” it “can be
adequately handled … [by] divid[ing] the class into
appropriate subclasses”). Whether that would necessitate the
creation of so many subclasses as to defeat the benefit of class
treatment is something I do not venture to conclude on this
record. But I would remand the case to the District Court for
consideration of the feasibility of subclasses.

III. Conclusion

For the foregoing reasons, I would vacate the District
Court‟s certification order to the extent it provides for a single
class as to proof of damages and remand the case for the
District Court to address whether Dr. McClave‟s model
could, in fairness, be revised to accurately reflect the
conditions that would have existed in the Philadelphia DMA
in the absence of any reduction in overbuilding caused by
clustering. I would further ask the District Court to consider
whether the class certified for proving antitrust impact can be
divided into appropriate subclasses for purposes of proving
damages.

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