Appellants Kennecott Corp., Morton Thiokol, Inc., Barrick Resources (USA) Inc., and Hercules, Inc. (collectively “the taxpayers”), brought an action against the *1100Utah State Tax Commission and several county and state tax officials (collectively “the tax collectors”). The taxpayers contend that section 17-19-15 of the Code, which imposes a levy to provide funds to cover expenses incurred by Utah’s counties in assessing, collecting, and distributing property taxes, is unconstitutional.1 The taxpayers advance claims of invalidity under three separate constitutional provisions: (i) the fourteenth amendment of the United States Constitution, (ii) article XIII, section 5 of the Utah Constitution, and (iii) article I, sections 7 and 24 of the Utah Constitution. U.S. Const, amend. XIV; Utah Const, art. XIII, § 5; Utah Const, art. I, §§ 7, 24. The complaint seeks an injunction against the enforcement of section 17-19-15 and the recovery of taxes paid under protest.
The taxpayers filed a motion for partial summary judgment, asking for judgment on one of their three claims of unconstitutionality, specifically, a declaration that section 17-19-15 violates article XIII, section 5 of the Utah Constitution.2 The tax collectors filed a cross-motion for summary judgment, asking the court to hold section 17-19-15 constitutional on all three grounds raised in the complaint.
The district court denied the taxpayers’ motion and granted the tax collectors’ motion, but only in part. The court held that the taxpayers lacked standing to raise the article XIII, section 5 claim. The court declined to grant summary judgment on the other constitutional claims, and they remain before the trial court. The trial court certified its article XIII, section 5 ruling for immediate appeal under rule 54(b). Utah R.Civ.P. 54(b). The taxpayers then appealed the grant of partial summary judgment.
The first issue we address is not raised by either party, to wit: whether the otherwise unappealable interlocutory order of the district court was properly certified under rule 54(b) and is therefore properly before us. As we have noted previously, the failure of a party to raise an issue of subject matter jurisdiction is not disposi-tive. “[Ajcquiesence of the parties is insufficient to confer jurisdiction and ... a lack of jurisdiction can be raised at any time by either party or by the court.” Olson v. Salt Lake City School Dist., 724 P.2d 960, 964 (Utah 1986); see also Utah Restaurant Ass’n v. Davis, 709 P.2d 1159, 1160 (Utah 1985); Bailey v. Sound Lab, Inc., 694 P.2d 1043, 1044 (Utah 1984). We raise it here, sua sponte, as we did in Olson.
The initial question of whether an order is eligible for certification under rule 54(b), i.e., whether the order is “final,” is a question of law. See Pate v. Marathon Steel Co., 692 P.2d 765 (Utah 1984); Little v. Mitchell, 604 P.2d 918 (Utah 1979); see also Curtis-Wright Corp. v. General Elec. Co., 446 U.S. 1, 11, 100 S.Ct. 1460, 1466, 64 L.Ed.2d 1 (1980). Therefore, we review the trial court's decision on this point for correctness. See, e.g., Scharf v. BMG Corp., 700 P.2d 1068, 1070 (Utah 1985).
Rule 54(b) of the civil rules permits the trial court to certify certain interlocutory orders and, by so doing, force the appellate court to entertain the appeal. See Pate, 692 P.2d at 767-68. Rule 54(b) reads in pertinent part:
When more than one claim for relief is presented in an action, whether as a claim, counterclaim, cross-claim, or third-party claim, and/or when multiple parties are involved, the court may direct the entry of a final judgment as to one or more but fewer than all of the claims or parties only upon an express determination by the court that there is no just *1101reason for delay and upon an express direction for the entry of judgment.
Utah R.Civ.P. 54(b).
In Pate, we described in different words the three requirements for proper certification under rule 54(b):
First, there must be multiple claims for relief or multiple parties to the action. Second, the judgment appealed from must have been entered on an order that would be appealable but for the fact that other claims or parties remain in the action. Third, the trial court, in its discretion, must make a determination that “there is no just reason for delay” of the appeal.
Pate, 692 P.2d at 767 (quoting 10 C. Wright, A. Miller & M. Kane, Federal Practice and Procedure: Civ. 2d § 2656, at 47-48 (1983)).
In the present case, we focus on the second of the Pate criteria: Was the order upon which the judgment and certification entered one that would otherwise have been appealable absent the other claims? This is what is meant by the language in rule 54(b) that the certified order be one that could be characterized as a “final judgment as to one or more ... of the claims_” Utah R.Civ.P. 54(b) (emphasis added). Such a final order must “ ‘wholly’ dispose of one or more, ‘but fewer than all,’ of the claims or parties.” Olson, 724 P.2d at 964 (quoting Pate, 692 P.2d at 768). As we stated in Olson:
“ ‘Finality,’ for purposes of the application of Rule 54(b), is generally understood as that degree of finality required to meet the appealability requirements of 28 U.S.C. § 1291. [Citations omitted.] This, in turn, is usually defined as a judgment ‘which ends the litigation on the merits and leaves nothing for the court to do but execute the judgment.’ ” Catlin v. United States, 324 U.S. 229, 233 [65 S.Ct. 631, 633, 89 L.Ed. 911] ... (1945).
Olson, 724 P.2d at 964-65 (quoting Acha v. Beame, 570 F.2d 57, 62 (2d Cir.1978)) (bracketed material in original).
Although these cases may aid in understanding the term “final” as used in the rule, they do not answer the difficult question of when there is such a final determination of what can be characterized as “a separate claim.” As a leading treatise has noted, determining whether the trial court’s disposition of some but not all parts of a cause of action is a final judgment for purposes of rule 54(b) is not an easy task:
The line between deciding one of several claims and deciding only part of a single claim is sometimes very obscure. Difficulties even occur in a case that clearly involves multiple claims because the rule requires that the entirety of at least one of those claims be decided with finality. There is no generally accepted test that is used to determine whether more than one claim for relief is before the court.
10 C. Wright, A. Miller & M. Kane, Federal Practice and Procedure: Civ.2d § 2657, at 60-61. Although we have addressed rule 54(b) relatively often in recent cases, no Utah decision has considered this issue in depth. See Lane v. Messer, 731 P.2d 488 (Utah 1986); Olson v. Salt Lake City School Dist., 724 P.2d 960 (Utah 1986); Williams v. State, 716 P.2d 806 (Utah 1986); Pate v. Marathon Steel Co., 692 P.2d 765 (Utah 1984).
In determining the standard for “finality” of a separate claim under rule 54(b), some background is useful. The historical rule is that except in a narrow category of situations, no order of a trial court is ap-pealable until a final judgment is entered on all issues. Attorney Gen. of Utah v. Pomeroy, 93 Utah 426, 73 P.2d 1277 (1937). At that point, the final judgment and all preceding interlocutory orders may be reviewed. Pate, 692 P.2d at 767-68. The principle underlying this rule is that interlocutory appeals should be avoided because they present appellate courts with multiple appeals involving narrow issues taken out of the context of the whole case which slow down the final determination of the matter. Pomeroy, 93 Utah at 447-48, 73 P.2d at 1287; see Local P-171, Amalgamated Meat Cutters and Butcher Workmen of N. Am. v. Thompson Farms Co., 642 F.2d 1065, 1070-71 (7th Cir.1986) (decided under the federal rule); Advisory Committee on *1102Rules for Civil Procedure, Report of Proposed Amendments, reprinted in 5 F.R.D. 437, 472 (1946) (discussing federal rule).
Over the years, however, certain exceptions to this rule against interlocutory appeals have developed in recognition of the fact that under certain circumstances, the reasons for permitting a particular interlocutory appeal or class of appeals are sufficient to overcome the policies underlying the general rule requiring finality. See Pomeroy, 93 Utah at 471-72, 73 P.2d at 1297. One approach to allowing interlocutory appeals is expressed in rule 54(b) of the Federal Rules of Civil Procedure and its Utah counterpart, also denominated rule 54(b). See Fed.R.Civ.P. 54(b); Utah R.Civ.P. 54(b). This approach gives power to the trial court to certify a certain class of orders and thereby make them appeal-able as of right, effectively forcing the appellate court to review them. The federal rule, adopted in 1937, was essentially copied when the federally modeled Utah Rules of Civil Procedure were first implemented in 1950.
A second approach to allowing interlocutory appeals is contained in Utah Rule of Appellate Procedure 5 and its predecessor, Utah Rule of Civil Procedure 72(b), originally adopted in 1950. See Utah R.App.P. 5; Utah R.Civ.P. 72(b) (1950) (repealed 1985). Under this approach, the appellate court, rather than the trial court, is given control over which interlocutory orders may be appealed. Rule 5 permits an appellate court to grant a party leave to appeal from any interlocutory order entered by a trial court. However, the rule informs the parties that appellate courts will permit such appeals only when there are good reasons for departing from the general rule that appeals should be taken only from final judgments. “An appeal from an interlocutory order may be granted only if it appears that the order involves substantial rights and may materially affect the final decision or that a determination of the correctness of the order before final judgment will better serve the administration and interests of justice.” Utah R.App.P. 5(e).
It is important to note that Utah has a long history of permitting interlocutory appeals under certain circumstances, subject always to the discretionary control of the appellate court. This analogue to the right recognized in Utah Rule of Appellate Procedure 5(b) was clearly recognized in Attorney General of Utah v. Pomeroy, 93 Utah 426, 73 P.2d 1277 (1937), if not before. See Ketchum Coal Co. v. Pleasant Valley Coal Co., 50 Utah 395, 404-05, 168 P. 86, 89 (1917). In Pomeroy, Justice Wolfe stated that what amounts to an appeal could be entertained by an appellate court whenever it determined it was in the interest of the equitable administration of justice to do so. Pomeroy, 93 Utah at 471-72, 73 P.2d at 1297-98.
In 1950, this law became part of the Utah Rules of Civil Procedure through the adoption of rule 72(b). In the notes explaining this rule, the compilation committee noted that this was a new provision to Utah’s procedural rules and was borrowed from the Iowa rules of procedure and based on Utah court decisions that permitted appeal of interlocutory orders under a special writ. Utah R.Civ.P. 72(b) (1950) (repealed 1985) (compiler’s notes). The compiler’s note stated that the “rule will make it possible for the Supreme Court to allow an interlocutory appeal where such a review would be in the best interests of justice.” Id. At this point, there was no federal counterpart to rule 72(b).
With this background, we proceed to examine the finality requirements of separate claims of Utah Rule of Civil Procedure 54(b). Because rule 54(b) of the Utah rules is taken from the Federal Rules of Civil Procedure, we freely look to federal authority interpreting that rule. See Olson, 724 P.2d at 965 n. 5; Pate, 692 P.2d at 767 n. 1. However, we certainly are not bound by any particular federal interpretation, especially where the rules operate in different underlying environments.
The federal courts have taken two basic approaches to determining when a claim is separate and an order disposing of it is eligible for treatment as a “final” judgment and certification under rule 54(b). *1103The first is exemplified by the Seventh Circuit. It requires that before a claim can be considered separate, the facts underlying it must be different than those underlying other claims in the action. See Indiana Harbor Belt R.R. v. American Cyanamid Co., 860 F.2d 1441, 1445 (7th Cir.1988); Automatic Liquid Packaging, Inc. v. Dominik, 852 F.2d 1036, 1037 (7th Cir.1988); Jack Walters & Sons Corp. v. Morton Bldg., Inc., 737 F.2d 698, 702 (7th Cir.1984).3 The Seventh Circuit takes the position that several legal theories based on one set of facts do not convert the theories into separate claims for purposes of rule 54(b). Indiana Harbor, 860 F.2d at 1445.
In determining the separateness of a claim, the Seventh Circuit “focuses on the degree of factual overlap between the issue certified for appeal and the issues remaining in the district court.” Id.; see also Dominik, 852 F.2d at 1037; National Metalcrafters v. McNeil, 784 F.2d 817, 821 (7th Cir.1986); FDIC v. Elefant, 790 F.2d 661, 664 (7th Cir.1986). When this factual overlap is such that separate claims appear to be based on the same operative facts or on the same operative facts with minor variations, they are held not to constitute separate claims for rule 54(b) purposes. See, e.g., Indiana Harbor, 860 F.2d at 1445; Dominik, 852 F.2d at 1037; Elefant, 790 F.2d at 664; McNeil, 784 F.2d at 821; Jack Walters, 737 F.2d at 702; Minority Police Officers Ass’n v. City of South Bend, 721 F.2d 197, 200 (7th Cir.1983).
The Seventh Circuit’s approach is based on what the court “perceive[d] to be the most important purpose behind the drafters’ decision to confine the scope of Rule 54(b) to situations where one of multiple claims is fully adjudicated — ‘to spare the court of appeals from having to keep relearning the facts of a case on successive appeals.’ ” Indiana Harbor, 860 F.2d at 1444 (quoting Jack Walters, 737 F.2d at 702); cf. Pomeroy, 93 Utah at 470-72, 73 P.2d at 1297-98.
The second federal line of authority on the definition of a separate claim is exemplified by the approach of the Second Circuit. That approach is more liberal in that it makes a broader range of orders eligible for certification under rule 54(b). “The ultimate determination of multiplicity of claims must rest in every case on whether the underlying factual bases for recovery state a number of different claims which could have been separately enforced.” Reiser v. Baltimore & Ohio R.R., 224 F.2d 198, 199 (2d Cir.1955). Under this approach, multiple claims for relief exist when the “possible recoveries are more than one in number and not mutually exclusive or, stated another way, when the facts give rise to more than one legal right or cause of action.” 10 C. Wright, A. Miller & M. Kane, Federal Practice and Procedure: Civ.2d § 2657, at 67 (citations omitted). This is the approach taken by Justice Stewart’s concurrence today.
The motive for the Second Circuit’s adoption of this approach was to ease the obstacles to 54(b) interlocutory appeals in response to the adoption of liberal joinder rules which could conceivably create an injustice for litigants who were forced to await the resolution of the entire case even though their rights on some issues had perhaps been conclusively resolved. Collins v. Metro-Goldwyn Pictures Corp., 106 F.2d 83, 85 (2d Cir.1939). This concern reflects the consensus of the federal rule makers of 1938. Prior to the adoption of the Federal Rules of Civil Procedure, at a time when litigation was generally conducted by two parties and was limited to one claim, courts generally required a final determination on all claims prior to appeal. Sears, Roebuck & Co. v. Mackey, 351 U.S. 427, 431-32, 76 S.Ct. 895, 897, 100 L.Ed. 1297 (1956). However, with the adoption of liberal joinder rules in 1938, there was concern that in some instances there might be a need to allow interlocutory appeals prior to a final determination of the case. See Advisory Committee on Rules for Civil *1104Procedure, Report of Proposed Amendments, reprinted, in 5 F.R.D. 437, 472 (1946). Since at that time there was no federal analogue to our rule of appellate procedure 5 permitting appeals from any interlocutory order under control of the appellate courts, the federal rule makers proposed rule 64(b), which vested control in the trial courts.
In 1958, Congress adopted 28 U.S.C. section 1292, which takes the approach of our appellate rule 5(b) and permits interlocutory appeals under control of the appellate courts, but only in a rather narrow set of circumstances where a trial judge has also agreed that the issues warrant appellate review. See Advisory Committee Notes to 1963 amendments. This provision is not nearly as broad as our rule 5(b), which permits an appellate court to authorize the taking of an appeal from any order of a trial court without the trial court’s approval.4
In light of the different situations that obtain in the Utah courts and the federal courts regarding the opportunities for review of interlocutory orders, we find the reasons advanced by the Second Circuit for giving federal rule 54(b) a broad reading inapposite when construing the Utah rule. Despite the fact that we copied federal rule 54(b), our need for it was never as great as the federal courts’, and certainly has been less since the 1950 adoption of civil rule 72, the predecessor to appellate rule 5.
Moreover, while a narrow approach to 54(b) certifications does not limit the availability of interlocutory appeals in Utah, it does have the advantage of giving the appellate courts greater control over their dockets. Our experience suggests that district courts rather freely grant certifications, often without examining closely the certifiability of the underlying order. See, e.g., Olson v. Salt Lake City School Dist., 724 P.2d 960 (Utah 1986). A 54(b) certification has relatively little consequence for the trial court, but it does force the appellate court to review a district court order whether or not the appellate court thinks there was error and without regard to the delays that may result from a piecemeal appeal. If fewer orders are certifiable under 54(b), those seeking to appeal from interlocutory orders will have to convince the appellate court that there is good reason to permit the appeal under rule 5 of the Utah Rules of Appellate Procedure, an entirely wholesome result.
Based on the foregoing, we conclude that the Seventh Circuit’s approach is more in line with our needs than that of the Second Circuit. Utah’s rules of appellate procedure provide ample avenues for interlocutory appeals.
We recognize that the “factual overlap” approach of the Seventh Circuit is dependent on the facts of each case and that the operation of this standard will have to be fleshed out over time. One important factor that is followed by the Seventh Circuit and others in determining whether the operative facts underlying the order that is claimed eligible for 54(b) certification is the res judicata effect that determination would have on the issues remaining before the trial court. See Dominik, 852 F.2d at 1037; Local P-171, Amalgamated Meat Cutters v. Thompson Farms Co., 642 F.2d 1065, 1070 (7th Cir.1981).5 Where the facts *1105are sufficiently similar to constitute res judicata on the remaining issues, 54(b) certification is generally precluded. Although this factor may not always be determinative, Minority Police Officers, 721 F.2d at 200, it is an important consideration.
Turning to the facts of the present case, we conclude that the trial court erred in determining that its order was a final order eligible for certification. Under the analytical approach we adopt today, the key question is whether there is factual overlap between the ostensibly separate claims. Here, the overlap is total. The taxpayers’ claims are all based on the same underlying facts. Their other constitutional arguments are really only different theories of constitutional invalidity. It would be a waste of judicial resources to have this court learn the facts of the case in order to determine the propriety of the trial court’s decision under article XIII, section 5 of the Utah Constitution, when at a later time we would be forced to review a variant challenge to the same statute on the same facts.6
Because the issue certified to this court is based on facts that substantially overlap those facts that serve as the basis for other theories pending before the district court, this appeal is dismissed as erroneously certified under rule 54(b).
HALL, C.J., and DURHAM, J., concur. HOWE, Associate C.J., concurs in the result.. We decided the constitutionality of section 17-19-15 in Mountain States Tel. & Tel. Co. v. Garfield County, 811 P.2d 184 (Utah 1991).
. Article XIII, section 5 provides as follows:
The Legislature shall not impose taxes for the purpose of any county, city, town or other municipal corporation, but may, by law, vest in the corporate authorities thereof, respectively, the power to assess and collect taxes for all purposes of such corporation. Notwithstanding anything to the contrary contained in this Constitution, political subdivisions may share their tax and other revenues with other political subdivisions as provided by statute.
Utah Const, art. XIII, § 5.
. Several states also follow this approach. See, e.g., Cole v. Peterson Realty, Inc., 432 A.2d 752, 755 (Me.1981); Las Vegas Hacienda v. G.L.M.M. Corp., 93 Nev. 177, 561 P.2d 1334, 1335 (1977); Ochs v. Northwestern Nat'l Life Ins. Co., 254 N.W.2d 163, 167 (S.D.1977).
. 28 U.S.C. section 1292(b) provides:
When a district judge, in making in a civil action an order not otherwise appealable under this section, shall be of the opinion that such order involves a controlling question of law as to which there is substantial ground for difference of opinion and that an immediate appeal from the order may materially advance the ultimate termination of the litigation, he shall so state in writing in such order. The Court of Appeals which would have jurisdiction of an appeal of such action may thereupon, in its discretion, permit an appeal to be taken from such order, if application is made to it within ten days after the entry of the order: Provided, however, That application for an appeal hereunder shall not stay proceedings in the district court unless the district judge of the Court of Appeals or a judge thereof shall so order.
28 U.S.C. § 1292(b) (Supp.1991).
. This res judicata approach is followed by other courts as well. See Tolson v. United States, 732 F.2d 998, 1001 (D.C.Cir.1984); Gold Seal Co. v. Weeks, 209 F.2d 802, 809-10 (D.C.Cir.1954); Page v. Preisser, 585 F.2d 336, 339 (8th Cir.1978) ("[R]ule [54(b) ] did not ... purport to amend *1105or dilute the fundamental rule against splitting a cause of action.”).
. Even under the liberal approach cited in the concurrence, the judge’s order was not final because under any theory the taxpayers espoused, they sought the same remedy: a declaration that the statute was unconstitutional and reimbursement for taxes paid under protest.