This case involves the extent to which telephone bills for telephones used by the Governor and two of his staff members, and the Governor’s unpublished appointment schedules, are subject to public disclosure under the Maryland Public Information Act, Maryland Code (1984, 1999 Repl.Vol.), §§ 10-611 through 10-630 of the State Government Article.1
I.
In November and December 1996, the Washington Post Company (the Post), through its agents, reporters Mary Pat Flaherty and Charles Babington, requested telephone and scheduling records, pursuant to Maryland’s Public Information Act, from the Office of the Governor. Ms. Flaherty’s request sought the telephone records of “the Governor and his staff’ over a two-year period, including
“[a]ll phones in the Governor’s Mansion [Government House]; his State House offices; all phones in Shaw House (an annex office in Annapolis); all phones in the Washington and Baltimore offices; all car phones and cellular phones used by the governor and anyone on his staff.”
Mr. Babington’s request for appointment or scheduling records was limited to the Governor but also spanned a two-year period. He requested
“[a]ll calendars indicating the persons, times, dates, and locations of meetings involving Governor Glendening in his official capacity as governor. This should include meetings *527in his State House office as well as those in Baltimore and other places where the governor conducts business.”
Both requests were granted in part and denied in part.
The Office of the Governor (the Office) provided Ms. Flaherty with the aggregate cost of the telephone calls specified in her request; however, it denied the release of any “call detail,” including the date, time, and length of each call. The Office asserted executive privilege, citing § 10-618(b) of the Act and this Court’s opinion in Hamilton, Superintendent v. Verdow, 287 Md. 544, 414 A.2d 914 (1980), as well as cases in other states holding that telephone and scheduling records are exempt from disclosure under their corresponding public information acts.2 The Office released the Governor’s public agendas to Mr. Babington but denied the remainder of his request, stating that the appointment or scheduling records were not “public records” within the meaning of § 10-611(g) of the Act, and also invoking executive privilege, citing § 10-618(b) and Hamilton.3
Negotiations between the parties continued throughout much of 1997, and during that time the Post narrowed its request. With respect to telephone records, the Post limited its request to the telephone records of calls by the Governor, Chief of Staff Major E. Riddick, Jr., Senior Advisor Susan Smith-Bauk, and Secretary of State John F. Willis, over the *528six-month period from February 1, 1996, through July 31, 1996. In addition, Mr. Babington’s original request for appointment records was also limited to the same six-month period. Despite these changes, the Office still refused to comply with the Post’s request.
As a result, on December 4, 1997, the Post brought suit in the Circuit Court for Anne Arundel County against the Office of the Governor and Governor Parris Glendening. Under the Post’s complaint, the records sought were those asked, for after the Post had narrowed its request, namely records of telephone calls by specified individuals and appointments of the Governor, covering only the six-month period. The Office and the Governor filed a motion for summary judgment, claiming that all of the records fell within § 10 — 618(b) and the doctrine of executive privilege. They also argued that public disclosure of the Governor’s daily schedules, even after the fact, would pose a threat to the personal security of the Governor and those around him.4 In addition, they claimed that some of the documents were also exempt from disclosure under other sections of the Act, specifically the exemptions for *529records containing confidential personnel information (§§ 10-616(d) and (i)), confidential commercial information (§ 10-617(d)), confidential employee information (§ 10-617(e)), or confidential financial information (§ 10-617(f)). The defendants argued that these specific exemptions under the Act would require redactions that were “virtually impossible to accomplish.” Finally, they argued that the Post’s request for the telephone records of Secretary of State Willis was barred because he had not been joined as a party to the action.
Pursuant to an order of the court, the Governor and his office submitted in camera sample copies of the appointment schedules and telephone records, as well as affidavits from the Governor and numerous staff members, including Joanne Trumbule, the Governor’s Director of Scheduling, Robert Plat-ky, the Director of Financial Administration for the Office of the Governor, and State Police Lieutenant Gary Shields, Commander of the Governor’s Protection Unit.
The Post filed a cross motion for summary judgment, arguing that the documents at issue were not “interagency or intra-agency letter[s] or memorand[a]” within the meaning of § 10-618(b) of the Act, and that, as purely factual material, the documents were not privileged. According to the Post, any threat to the Governor’s security as a result of the release of the requested records, even if true, did not constitute an “independent justification recognized under the [Act] for withholding public records.” Finally, the Post contended that the exemptions claimed for commercial information, financial information, and personnel records did not apply to the records at issue and that, alternatively, even if parts of the records were within such exemptions, the defendants were not justified in withholding all of the records.
A hearing was held on the motions for summary judgment in May 1998. In early July 1998, the Circuit Court issued an opinion and order denying the motions. The court held that the doctrine of executive privilege was incorporated into the Act in both § 10-618(b), as argued by the Office and the Governor, and also in § 10-615(1), which requires non-disclo*530sure when “by law, the public record is privileged or confidential.” As a result, the court held that whether the documents fit within the definition of “memorandum” under § 10-618(b) was irrelevant if the documents were privileged under the doctrine of executive privilege. Citing Hamilton, Superintendent v. Verdow, supra, 287 Md. 544, 414 A.2d 914, the Circuit Court found that a purpose of that privilege “is to promote the efficient operation of the government by allowing the Governor to solicit advice from a wide range of people without fear that public disclosure will restrain the free flow of that advice.” The court also stated that the privilege was not absolute, and that the evidence was insufficient to determine whether the records might be privileged under § 10-618(b) and/or § 10-615(1). Accordingly, the court ordered the defendants to produce all telephone and scheduling records to the Post for which the defendants were not claiming privilege, submit to the court for an in camera review all records claimed to be privileged, and submit to the court a proposed redacted version of those records with a detailed memorandum explaining why the redacted information was privileged.
Two weeks after the Circuit Court’s opinion and order, the Post filed a motion requesting the court to set a compliance deadline for the defendants. One week later, the defendants filed a motion for clarification and reconsideration, again asking the court to recognize a categorical executive privilege as to all documents at issue and asserting that compliance with the opinion and order would be excessively burdensome. After a hearing, the court granted the Post’s motion and set the compliance deadline for September 5, 1998, which was subsequently extended to September 11, 1998. The court denied the defendants’ motion for reconsideration, stating that “[t]he court does not believe that the Governor is entitled to a broad claim of executive privilege on all telephone and calendar records,” but that he “may be entitled to executive privilege if [he] can prove that disclosure of particular information will adversely affect [his ability] to effectively carry-out his Constitutional duties.” The court also held that the telephone records of Secretary of State John F. Willis were not within *531the scope of the court’s July opinion and order because the Post had failed to name the Secretary of State as a party.
The Office and the Governor on September 11, 1998, submitted a limited group of records to the Post, including the telephone records from the business line in Mr. Riddick’s home, other telephone records at issue with call detail redacted so that only the cost was revealed, and reimbursement receipts for personal calls made by Mr. Riddick and Ms. Smith-Bauk for the six months at issue. They submitted to the court, for in camera review, unredacted copies of the telephone and calendar records with proposed redactions highlighted, as well as a memorandum and affidavits in support of those redactions.
On September 15,1998, the Post filed a motion to unseal the in camera explanations for the redactions, and thereafter argument on this motion was heard before the Circuit Court. The court issued its final order on October 23,1998, in which it held
“that the Defendants, with limited exceptions, have failed to make a particularized showing as to executive privilege, and further have failed to satisfy the statutory burden of demonstrating that the records at issue are exempt from mandatory disclosure under the Maryland Public Information Act.”
The court granted the Post’s motion to unseal the in camera explanations, and ordered that the Office and the Governor produce to the Post “complete and unredacted copies of all of the telephone and calendar records at issue.... ” Finally, in anticipation of an appeal, the court stayed the execution of the order and retained the records submitted in camera for ninety-six hours.
The Office and the Governor immediately filed a notice of appeal and sought a stay of the Circuit Court’s judgment. The Court of Special Appeals granted the motion to stay the judgment. Before any further proceedings in the Court of Special Appeals, this Court issued a writ of certiorari. Office of the Governor v. Washington Post, 352 Md. 309, 721 A.2d 988 (1998).
*532II.
As noted earlier, supra note 3, the Maryland Public Information Act in § 10 — 611(g) defines “public record” as “the original or any copy of any documentary material that: (i) is made by a unit or instrumentality of the State government or of a political subdivision or received by the unit or instrumentality in connection with the transaction of public business ----” Section 10-613(a) provides that, unless a record is
exempted by law, a custodian “shall permit a person ... to inspect any public record at any reasonable time.” Sections 10-615 through 10-619 provide for exemptions and permissible denials.
A.
A threshold question in this case, raised during the course of questioning by the Court at the initial oral argument, is whether the Act is applicable to the Office of the Governor. This issue had not been raised below and had not been briefed by the parties. As might be expected, however, the defendants suggest that the Act is not applicable and the plaintiff contends that it is fully applicable.5
*533The Maryland Act, originally enacted and codified in 1970 as Maryland Code (1957, 1975 Repl.Vol.), Art. 76A, §§ 1 through 5, was to some extent modeled after the Federal Freedom of Information Act, 5 U.S.C. § 552, enacted in 1966. The Federal Act has been construed as not applying to the Office of the President. See Kissinger v. Reporters Committee for Freedom of the Press, 445 U.S. 136, 100 S.Ct. 960, 63 L.Ed.2d 267 (1980). By analogy, it was suggested that the State Act should not apply to the Office of the Governor. Because the text and history of the Maryland Act differ from the language and history of the Federal Act in several significant ways, however, we believe that this analogy is flawed.
The records subject to the Federal Act, unlike those subject to the Maryland Act, are “agency records.” Although that term was not originally defined in the Federal Act, by amendments to the Act in 1974 “agency” was defined as follows (5 U.S.C. § 552(f)):
“any executive department, military department, Government corporation, Government controlled corporation, or other establishment in the executive branch of the Government (including the Executive Office of the President), or any independent regulatory agency.”
This section of the Federal Act was construed by the Supreme Court in Kissinger v. Reporters Committee for Freedom of the Press, supra, 445 U.S. 136, 100 S.Ct. 960, 63 L.Ed.2d 267. In that case, a journalist, William Safire, sought written transcripts of telephone conversations between Henry Kissinger6 and certain White House officials concerning “leaks,” and any calls mentioning Mr. Satire’s name. The Supreme Court upheld the denial of the request, holding that, although the *534Federal Act includes the “Executive Office of the President” as an agency subject to the Act, it did not apply to the President’s immediate assistants and advisers, designated collectively as the Office of the President. The Court reached this conclusion based upon the House Conference Report for § 552(f) of the Federal Act which stated: “the President’s immediate personal staff or units in the Executive Office whose sole function is to advise and assist the President” are not included within the term “agency.” Kissinger, 445 U.S. at 156, 100 S.Ct. at 971, 63 L.Ed.2d at 285, quoting H.R.Conf. Rep.No. 93-1380, p. 15 (1974). As Mr. “Satire’s request was limited to a period of time in which Kissinger was serving as Assistant to the President,” the Court held that the telephone records were not “agency records” at the time they were made. 445 U.S. at 156, 100 S.Ct. at 971, 63 L.Ed.2d at 285.
Although this issue has not been revisited in the Supreme Court, the scope of the Federal statute has been addressed by the United States Court of Appeals for the District of Columbia Circuit. That court has viewed the 1974 amendment to the Federal Act as a codification of its earlier holding in Soucie v. David, 448 F.2d 1067 (D.C.Cir.1971). In Soucie, the court held that the Office of Science and Technology was an “agency” subject to the Federal Act because it had “substantial independent authority,” and, therefore, its “sole function” was not “to advise and assist the President.” Id. at 1073, 1075. In Meyer v. Bush, 981 F.2d 1288, 1297 (D.C.Cir.1993), the court held that President Reagan’s Task Force on Regulatory Relief, headed by then Vice President Bush, and composed of several Cabinet members, was not an “agency” subject to the statute because it did not have “ ‘substantial independent authority.’ ” See Rushforth v. Council of Economic Advisers, 762 F.2d 1038 (D.C.Cir.1985) (Council of Economic Advisers is not an agency subject to Federal Act); Pacific Legal Found, v. Council on Envtl. Quality, 636 F.2d 1259 (D.C.Cir.1980) (Council on Environmental Quality is an agency subject to the statute).
The Maryland Act applies to “public records,” not “agency records.” The coverage of the Act is dependent upon the *535scope of the term “public records,” and not upon whether the governmental entity holding the records is an “agency” rather than some other type of governmental entity. Although this Court has examined the status of particular entities in order to determine if their records were covered by the Act, such examinations were for the purpose of deciding whether the entities were private or governmental. In each of these cases, the entities argued that they were private and that, for this reason, their records were not “public records” subject to disclosure under the Act. In each case, this Court held that the entities were governmental instrumentalities for purposes of the Act and that, therefore, their records were covered by the Act.
For example, in holding that the Maryland Insurance Guaranty Association was a governmental instrumentality for purposes of the Act, this Court in A.S. Abell Pub. Co. v. Mezzanote, 297 Md. 26, 32, 464 A.2d 1068, 1071 (1983), emphasized that the Act broadly covers any part of Maryland government:
“The Public Information Act provides that the public is entitled to information regarding the affairs of government .... To that end, the Public Information Act provides that the public has the right to inspect the public records of any branch of the State government.... Moreover, the Public Information Act expressly states that its provisions ‘shall be broadly construed in every instance with the view toward public access,’.... Thus, the provisions of the Public Information Act reflect the legislative intent that citizens of the State of Maryland be accorded wide-ranging access to public information concerning the operation of their government. Accordingly, in determining whether MIGA is an agency or instrumentality of the State within the scope of the Public Information Act, the language ... must be liberally construed in favor of inclusion in order to effectuate the Public Information Act’s broad remedial purpose.” (Citations omitted).
And in Moberly v. Herboldsheimer, 276 Md. 211, 228, 345 A.2d 855, 864 (1975), interpreting the Public Information Act to *536encompass the hospital records of a corporation known as the Memorial Hospital of Cumberland, we concluded:
“If the General Assembly did not intend this interpretation when it enacted this far reaching statute, it should so state.”
According to § 10-611(g) of the State Government Article, the Maryland Public Information Act applies to “any documentary material that ... is made by a unit or instrumentality of the State government ... or received by the unit or instrumentality in connection with the transaction of public business.” Unlike the Federal Act, there is no statutory language or legislative history suggesting that any unit of the Maryland Government is exempt from the Public Information Act’s coverage. The grounds for the Supreme Court’s interpretation of the Federal Act in Kissinger v. Reporters Committee for Freedom of the Press, supra, do not exist with regard to the Maryland Act. On the contrary, the cases interpreting the Maryland Act have broadly construed the terms “public record” and “instrumentality of the State government.” The offices of the Governor and his staff in the State House and Shaw House in Annapolis, as well as their offices in Baltimore and Washington, are clearly encompassed by the statutory language “unit or instrumentality of the State government.”
B.
There are, however, certain records requested by the Post which, in our view, are not “public records” for purposes of the Public Information Act. They are the records of telephone calls made from telephones in the “Governor’s Mansion” or, as it is officially named, “Government House.”
As previously discussed, apart from the statute’s express exemptions, the coverage of the Maryland Public Information Act is ordinarily dependent upon whether records are those of a “government instrumentality” or are “private.” A.S. Abell Pub. Co. v. Mezzanote, supra, 297 Md. at 30-31, 464 A.2d at 1070; Moberly v. Herboldsheimer, supra, 276 Md. 211, 345 A.2d 855. Moreover, “there is no single test for determining *537whether a statutorily-established entity is an agency or instrumentality of the State for a particular purpose,” and “[a]ll aspects of the interrelationship between the State and the ... entity must be examined,” Mezzanote, 297 Md. at 35, 464 A.2d at 1072.
It seems obvious that bills or records of telephone calls, made by a government official or members of the official’s family from their personal telephones in the family’s private home, would not be considered “public records” within the meaning of the Act. In light of one’s reasonable expectation of privacy in his or her own home, such records would be “private.”
Article II, § 21, of the Constitution of Maryland provides in pertinent part that “[t]he Governor shall reside at the seat of government....”7 The State, in the implementation of this provision, provides a home, named “Government House,” for the Governor and his family in the City of Annapolis. See Code (1984, 1999 Repl.Vol.), §§ 9-601 through 9-606 of the State Government Article (relating to the Government House Trust).
In light of the nature of Government House and the role of the Government House Trust, the Governor and his family might not have the identical expectations of privacy while living there as one has in his or her privately owned home. Nonetheless, we do not believe that the Governor and his family must relinquish all normal expectations of privacy in their home simply because, in accordance with constitutional and statutory provisions, their home and furnishings, including telephone service, are supplied by the State.
Unlike Chief of Staff Riddick, the Governor does not have a designated “business line” in Government House. The record in this case discloses that, with regard to the telephone bills for calls made from Government House, it would be almost *538impossible to determine which member of the family made particular calls or, even if it could be determined that a particular call was made by the Governor, whether it was personal or related to state business.
We do not believe that the General Assembly, in defining “public record” as a record “made by a unit or instrumentality of the State government” (§ 10-611(g)), intended to include the home telephone bills of the Governor and his family. Consequently, records of calls from telephones in Government House are not covered by the Act and need not be disclosed.8
III.
Before addressing the defendants’ principal arguments that the records sought by the Post fall within the Public Information Act’s exemptions, we can dispose of some matters based on availability and the scope of the Post’s requests.
The Post requested the telephone records of the Governor, Mr. Riddick, and Ms. Smith-Bauk from telephones in *539the State House and the Shaw House, which are both in Annapolis, from telephones in the Washington and Baltimore offices of the Governor, and from any cellular telephones used by these three individuals. The defendants produced in the Circuit Court a detailed account of the telephone system employed by the State, and the limitations of that system. In reviewing the record, we conclude that the Circuit Court should have excluded certain documents, or portions of documents, from disclosure based upon the unavailability of the documents or the Post’s own limitations on the scope of its requests.
A.
The first group of these documents consists of the telephone records from offices outside of the State House.
The telephone system in use in the Baltimore office, known as the “PBX system,” includes a “collection device” which records all incoming and outgoing local and long distance calls to and from that office. The only other telephone records from the Baltimore office are the bills from the long distance service provider, documenting only outgoing long distance charges. The petitioners produced several affidavits in the Circuit Court stating that, although the “external” long distance bills have been retained, the “internal” information collected by the PBX system is no longer available.
Louis LaRicci, the Deputy Director of the Division of Telecommunications in the Office of Information Technology within the Department of Budget and Management, stated in his affidavit that the billing information for the Governor’s Baltimore office, for the period from February 1, 1996, to July 31, 1996, “was disposed of in the ordinary course of the Division’s business.” Carol Cordial, the Assistant Director of the Division of Telecommunications, stated in her affidavit that the telephone records for the Baltimore office are “written over automatically by the system” every twelve months and that, therefore, “nc internal data currently is retained” for that office. The Post has not disputed these statements. The *540internal billing information from the Baltimore office is unavailable. Obviously, a custodian cannot properly be ordered to produce records under the Act when those records simply do not exist.
Although the long distance bills for the Baltimore office are currently in the possession of the Division of Telecommunications, they also need not be produced. The Post’s request was limited to the telephone records of the Governor, Ms. Smith-Bauk, and Mr. Riddick. The bills from the long distance service provider for the Baltimore office indicate only the line from which the calls originated and the number to which the calls were placed. They do not indicate who placed each call. Moreover, the record shows that the Governor, Mr. Riddick, and Ms. Smith-Bauk were rarely in the Baltimore office during the time period in question. As Mr. Riddick stated in his affidavit, “I did not work in that office any more than a few times each month during the six months at issue.” Ms. Smith-Bauk stated that she “did not often use ... [the office] or the telephones there.” The three officials’ possible use of the telephones in the Baltimore office during the time period in question, to make long distance calls, is far too speculative for treating the bills as telephone records of the Governor, Ms. Smith-Bauk, and Mr. Riddick. Accordingly, the long distance telephone bills for the Baltimore office are beyond the scope of the Post’s request for telephone records.
For the same reason, the telephone records of calls originating in Shaw House and the Washington, D.C., office are beyond the scope of the telephone records request. The record clearly shows that none of the three officials have either offices or designated telephone lines at these locations. In addition, Chief of Staff Riddick stated in his affidavit that “I cannot recall if I ever was in the Washington office from February through July 1996, and I certainly was not there with any regularity.” Ms. Smith-Bauk said essentially the same thing in her affidavit. The record is clear that the use of the telephones in both Shaw House and the Washington office by the three officials would have been rare, if it occurred at *541all, during the period in question. Consequently, the request for telephone billing records from these locations should also have been denied.
B.
The telephone records from the State House are numerous and complex. These records document only long distance calls. Carol Cordial, the Assistant Director of the Division of Telecommunications, explained this system in detail in her affidavit. To summarize, the offices of the Governor and Ms. Smith-Bauk are located within the same suite of offices, which is served by eighteen separate telephone lines. Five other people work in that suite and use the telephones. Because use of the different telephone instruments within the entire suite is not restricted, anyone within the suite can use any one of the instruments and, therefore, could access all eighteen lines. As a result, the telephone bills reveal the lines from which individual calls are made but do not, and cannot, reveal who placed each call. Mr. Riddick’s office, which is located in a separate suite, is also served by numerous telephone lines (seven in all), which can be accessed on separate instruments. Three assistants to Mr. Riddick also work in this suite and use the telephones. Again, the records from Mr. Riddick’s office do not reveal who placed the individual calls.
To repeat, the Post’s telephone records request was limited to the calls of the Governor, Mr. Riddick, and Ms. Smith-Bauk. Based on the scope of the request as well as the uncontradicted evidence, we believe that the trial court erred by not limiting the number of telephone lines at issue in the State House. Although it is difficult to determine who placed each call listed on the voluminous telephone bills, the lines at issue can be limited based upon the individual to whom the specific lines were assigned, and by whom they were most easily accessed and most frequently used. The Governor could access five lines directly from his immediate office, and Ms. Smith-Bauk could access six lines directly from her office (three of which were the same as three of the lines that the Governor could access). Finally, Mr. Riddick could access six *542lines from his office. Fourteen lines in all, they were designated in the record below as lines A, B, C, D, E, N, O, P, S, U, V, W, X, and Y. These are the lines from which it is reasonable to conclude that the three officials made most, if not all, of their calls while in the State House.
Therefore, we have limited the telephone records at issue to: (1) the fourteen lines from the State House as designated above, and (2) the cellular telephones assigned to the Governor, Ms. Smith-Bauk, and Mr. Riddick. These records are available and are, generally, within the scope of the Post’s request. Nevertheless, redactions within these records would seem to be in order because some individual entries appear to be beyond the scope of the Post’s request.
C.
In the records and documents submitted to the Circuit Court for in camera review, several items were designated as “Other Persons’ Calls,” meaning that they were made by persons other than the Governor, Ms. Smith-Bauk, and Mr. Riddick. Kelly Derthick, Executive Assistant to the Governor, Jennifer Crawford, Special Assistant to the Governor, and Anne Budowski, Senior Assistant to Chief of Staff Riddick, stated in their affidavits that they reviewed the telephone records from the State House and that they identified calls which they made themselves or which were placed by staff members other than the three officials. Ms. Budowski and Andrea Leahy-Fucheck, then Legal Counsel to the Governor, also stated in their affidavits that they reviewed the schedules of the Governor and the Chief of Staff and were able to identify time periods during which the two officials were out of the office and therefore could not have placed telephone calls. All of these calls were specifically identified and placed within the “Other Persons’ Calls” category in the material submitted to the trial court in camera. Unless, upon remand, the Circuit Court believes that it needs further information regarding the source of these calls, they would seem to be beyond the scope of the Post’s request and should be redacted.
*543The material submitted to the Circuit Court in camera also categorized individual calls placed on the cellular phones assigned to the Governor, Ms. Smith-Bauk, and Mr. Riddick. Similar to the calls identified as being made by “other persons” in the State House, calls from the three cellular phones assigned to the Governor were frequently made by the Maryland State Police troopers in the Executive Protection Unit and did not involve conversations of the Governor. Captain Gary Shields, Commander of the Executive Protection Unit, stated in his affidavit that he reviewed the bills from the Governor’s three cellular phones and, “[b]ased on the identification of the numbers called, the length of the calls, and their relationship to other calls,” he was “reasonably certain” that calls categorized in the “In Camera Schedule” under the heading “Executive Protection Unit” were calls by the troopers and not by the Governor. Again, unless the trial court on remand believes that it needs more information, these calls appear to be beyond the scope of the Post’s request and should be redacted from the records.
D.
As noted earlier, supra note 4, the Governor’s scheduling records include wholly personal meetings and family engagements. The defendants argue that such records should be exempt from disclosure. According to the Post’s brief in this Court, “[t]he Post advised the Circuit Court that it would not object to the redaction of calendar items corresponding to family events ... so long as there was a proper evidentiary showing supporting such redactions.” (Respondent’s brief at 45, n.29). The Circuit Court made no specific ruling that the defendants’ evidentiary showing in this regard was insufficient. Upon remand, unless the trial court desires more evidence that a particular calendar item is entirely personal or family, these items should be redacted based on the Post’s representation.
IV.
We next address the defendants’ arguments that various portions of the records fall within specific Public Information *544Act exemptions in §§ 10 — 616(d) and (i) (letters of reference and personnel records), 10-617(d) (commercial information), 10-617(e) (home addresses and telephone numbers of state or local government employees), and 10-618(b) (interagency or intra-agency letters or memoranda).9
A.
Preliminarily, however, it would be useful to underscore certain well-established general principles governing the interpretation and application of the Maryland Public Information Act. This Court recently reiterated in Kirwan v. The Diamondback, 352 Md. 74, 80-81, 721 A.2d 196, 199 (1998), that
“[t]he Maryland Public Information Act establishes a public policy and a general presumption in favor of disclosure of government or public documents. The statute thus provides (§ 10-612(a) and (b) of the State Government Article):
‘(a) General Right to information. — All persons are entitled to have access to information about the affairs of government and the official acts of public officials and employees.'
(b) General construction. — To carry out the right set forth in subsection (a) of this section, unless an unwarranted invasion of the privacy of a person in interest would result, this Part III of this subtitle shall be construed in favor of permitting inspection of a public record, with the least cost and least delay -to the person or governmental unit that requests the inspection.’ ”
Accordingly, as we pointed out in Kirwan, 352 Md. at 84, 721 A.2d at 200, “the statute should be interpreted to favor disclosure.” See also, e.g., Office of the Attorney General v. *545Gallagher, 359 Md. 341, 343, 753 A.2d 1036, 1037 (2000) (“the Act is to be construed in favor of disclosure”); Office of State Prosecutor v. Judicial Watch, Inc., 356 Md. 118, 134, 737 A.2d 592, 601 (1999) (“It is the policy of this State that its citizens have ‘access to information about the affairs of government’ ”); Fioretti v. Maryland State Board of Dental Examiners, 351 Md. 66, 73, 716 A.2d 258, 262 (1998) (the statute embodies the principle that citizens “ ‘be accorded wide-ranging access to public information’ ”); Mayor and City Council of Baltimore v. Maryland Committee Against the Gun Ban, 329 Md. 78, 80-81, 617 A.2d 1040, 1041 (1993); Cranford v. Montgomery County, 300 Md. 759, 771, 481 A.2d 221, 227 (1984) (“Without doubt the bias of the Md. Act is toward disclosure”); Faulk v. State’s Attorney for Harford County, 299 Md. 493, 506-507, 474 A.2d 880, 887 (1984); A.S. Abell Publishing Co. v. Mezzanote, supra, 297 Md. at 32, 464 A.2d at 1071; Superintendent v. Henschen, 279 Md. 468, 473, 369 A.2d 558, 561 (1977); Haigley v. Dept. of Health, 128 Md.App. 194, 226-227, 736 A.2d 1185, 1201-1202 (1999). Concomitantly, “courts must interpret the exemptions narrowly,” Fioretti v. Board of Dental Examiners, supra, 351 Md. at 77, 716 A.2d at 264.
Moreover, “the public agency involved bears the burden in sustaining its denial of the inspection of public records.” Fioretti 351 Md. at 78, 716 A.2d at 264. See Cranford v. Montgomery County, supra, 300 Md. at 771, 481 A.2d at 227 (“The custodian who withholds public documents carries the burden of justifying nondisclosure”). An in camera inspection by the trial court, while not always necessary, may in some cases be “needed in order to make a responsible determination on claims of exemptions.” Cranford, 300 Md. at 779, 481 A.2d at 231. In addition, if parts of a record are exempt but other parts can be revealed, the Act favors severability. See § 10 — 614(b)(3)(iii); Cranford, 300 Md. at 774, 481 A.2d at 228-229.
B.
In the material submitted to the Circuit Court for in camera review, the defendants identified certain appointment *546or scheduling records and telephone records which, they claimed, fell within the Act’s exemptions set forth in §§ 10-616(d) and (i). Section 10-616 provides in pertinent part as follows:
“(a) In general. — Unless otherwise provided by law, a custodian shall deny inspection of a public record, as provided in this section.
“(d) Letters of reference. — A custodian shall deny inspection of a letter of reference.
“(i) Personnel records. — (1) Subject to paragraph (2) of this subsection, a custodian, shall deny inspection of a personnel record of an individual, including an application, performance rating, or scholastic achievement information. (2) A custodian shall permit inspection by:
(i) the person in interest; or
(ii) an elected or appointed official who supervises the work of the individual.”
The telephone records which allegedly fell within the above-quoted exemptions were described as “Call to_re personnel matter” or “Call to_re appointments” or “Call to _re judicial appointments.”10 The appointment records, typically, would include the date and then read as follows: “2:30 pm — 3:00 pm_interview [Govs offc]” or “3:30 — 4:30 pm ___ re: Green Bag appointments @ Govs offc,” or “11:00 a.m. — 11:15 a.m. Interview,_,_County District Court [Gov’s offc.] *Andrea,” or “1:30 pm — 2:15 pm Interview w._for___ [Govs offc] *Judi.”11
*547The defendants’ argument, that the above-described types of records should have been redacted pursuant to § 10-616(d) and (i), finds no support in the plain language of the statute or the cases applying the “personnel records” exemption.
Clearly, none of the above-described records constitutes a “letter of reference.” When the Governor telephones or meets with someone for the purpose of obtaining information about a prospective appointee, a record, memorandum, or notes of the substance of their conversation might arguably fall within the exemption for a “letter of reference” if the exemption is not given a strict literal interpretation. But the mere fact that the Governor, or one of his staff, telephoned or met with an identified person to obtain information about a prospective appointee is certainly not “a letter of reference.”
With regard to the “personnel records” exemption, this Court in Kirwan, 352 Md. at 82-83, 721 A.2d at 200, stated:
“The term ‘personnel record’ is not expressly defined in the statute. Nonetheless, the language of subsection (i) discloses what type of documents the Legislature considered to be personnel records. The statute lists three categories of documents which are: (1) an application for employment; (2) performance rating; and (3) scholastic achievement. Although this list was probably not intended to be exhaustive, it does reflect a legislative intent that ‘personnel records’ mean those documents that directly pertain to employment and an employee’s ability to perform a job.”
The Court went on in Kirwan to point out that records which
“do not relate to [the employee’s] hiring, discipline, promotion, dismissal, or any matter involving his status as an employee .... do not fit within the commonly understood meaning of the term ‘personnel records.’ ” 352 Md. at 83, 721 A.2d at 200.
We concluded in the Kinvan opinion by stating that, in light of the Act’s policy favoring disclosure, the General Assembly did not intend “that any record identifying an employee would be exempt from disclosure as a personnel record.” 352 Md. at 84, 721 A.2d at 200.
*548The identification of the telephone number which the Governor or a member of his staff called, or the identification of someone with whom the Governor met, concerning a possible future appointment to a judgeship or position in the executive branch of state government, would not amount to a “personnel record” as defined in Kirwan. The simple record of what number was called, or with whom the Governor met, about possible future employment would not relate to the discipline, promotion, dismissal, status, job performance, or achievement of an existing or former employee. Again, while the substance of the conversations might in some cases fall in the category of “application for employment” or relate to “hiring,” the fact that the Governor or a staff member telephoned or met with an identified individual would not be a “personnel record” under any “commonly understood meaning of the term,” Kirwan, 352 Md. at 83, 721 A.2d at 200.
C.
Section 10-617(d) of the Public Information Act states in relevant part as follows:
“(d) Commercial information. — A custodian shall deny inspection of the part of a public record that contains any of the following information provided by or obtained from any person or governmental unit:
(1) a trade secret;
(2) • confidential commercial information.... ”
The defendants argue that the affidavits of the Governor and Chief of Staff Riddick identified specific telephone calls which involved “economic development projects,” or “sensitive and confidential negotiations over” such economic development projects, or “confidential efforts to resolve a strike in Maryland,” or “sensitive discussions relating to a major public transportation project.” (Petitioners’ brief at 47-48). The defendants maintain that “the circuit court should have found those calls to be exempt from disclosure under ... the specific statutory exemption for confidential commercial information ... [in] § 10-617(d).” (Id. at 47).
*549Again, while records, memoranda, or notes of what was said during these conversations might amount to “confidential commercial information,” the fact that the Governor or Mr. Riddick made a telephone call to a particular number is not itself, standing alone, “commercial” information. In order to so qualify, the defendants would need to explain, for in camera consideration by the court, why the record of each such allegedly sensitive telephone call, if turned over to the Post, would place the Post in the position of potentially jeopardizing government projects or negotiations at critical stages of development. When the trial court, on remand, reconsiders any exemption claimed under § 10-617(d), as now asserted or as amplified on remand, it may consider in the balancing test how the staleness that now inheres by virtue of the passage of time affects the “confidential” nature of any assertedly protected information.
D.
The Public Information Act in § 10-617(e) provides:
“(e) Public employees. — Subject to § 21-504 of the State Personnel and Pensions Article, a custodian shall deny inspection of the part of a public record that contains the home address or telephone number of an employee of a unit or instrumentality of the State or of a political subdivision unless:
(1) the employee gives permission for the inspection; or
(2) the unit or instrumentality that employs the individual determines that inspection is needed to protect the public interest.”
The defendants assert that, in the Circuit Court, they “specifically identified 94 telephone calls to State employees at home where the telephone records thus list the employee’s home telephone number. * * * [Defendants] did not argue for complete redaction of those calls; they argued only that the employees’ home telephone numbers must be redacted, leaving all other data about the calls.” (Petitioners’ brief at 49).
*550The Post counters that the defendants “failed to present the court with any evidentiary support for the claim — which, at a minimum, would have needed to include the names of the alleged employees whose numbers were being withheld, so that the validity of the proposed redactions could be tested.” (Respondents’ brief at 43, n.26).
The record discloses that affidavits by the Governor’s Legal Counsel and by the Senior Assistant to Chief of Staff Riddick, submitted in connection with the defendants’ motion for summary judgment, stated, either as a matter of the affiants’ personal knowledge or of the knowledge of other staff members -with whom they spoke, that the descriptions of various categories, including the category of employees’ home telephone numbers, were accurate. The trial judge did not specifically find that the evidence was insufficient to show that the 94 numbers were home telephone numbers of state employees.
With two exceptions which are inapplicable here, the statute flatly exempts from disclosure the home telephone numbers of state or local government employees. The only evidence submitted to the trial court indicates that the 94 numbers called were in fact home telephone numbers of state government employees. On remand these numbers should be redacted unless the trial court concludes that it needs more information. In this connection, we point out that, if the trial court requires the submission of the state employees’ names in order to verify that the numbers are in fact telephone numbers of state employees, such submission should be in camera. It would largely defeat the exemption for public employees’ home telephone numbers if their names were made public, thereby allowing anyone to look up their telephone numbers in a telephone directory. Under these circumstances, the exemption would effectively apply only to public employees with unlisted home telephone numbers. This would obviously not be consistent with the Legislature’s intent.
E.
Section 10-618 of the Maryland Public Information Act gives a custodian discretion to deny inspection of parts of *551specified categories of public records if the custodian believes that such inspection would be contrary to the public interest. One of those categories consists of “interagency or intra-agency letter[s] or memorand[a].” Thus, § 10-618(a) and (b) state as follows:
“ § 10-618. Permissible denials.
(a) In general. — Unless otherwise provided by law, if a custodian believes that inspection of a part of a public record by the applicant would be contrary to the public interest, the custodian may deny inspection by the applicant of that part, as provided in this section.
(b) Interagency and intra-agency documents. — A custodian may deny inspection of any part of an interagency or intra-agency letter or memorandum that would not be available by law to a private party in litigation with the unit.”
This permissible exemption for interagency and intra-agency letters or memoranda to some extent reflects that part of the executive privilege doctrine encompassing letters, memoranda or similar internal government documents containing confidential opinions, deliberations, advice or recommendations from one governmental employee or official to another official for the purpose of assisting the latter official in the decision-making function. Cranford v. Montgomery County, supra, 300 Md. at 772-774, 481 A.2d at 227-228. See also Hamilton, Superintendent v. Verdow, supra,, 287 Md. at 553-562, 414 A.2d at 920-924.
We shall later, in Part V of this opinion, consider whether any of the telephone and scheduling records might be exempt from disclosure under the doctrine of executive privilege and § 10-615(1) of the Maryland Public Information Act. Regardless of whether some of the records might be exempt as “privileged” material under § 10-615(1), however, it seems obvious that a bill from a telephone company or a simple scheduling record does not constitute “an interagency or intraagency letter or memorandum” under § 10-618(b).
*552Preliminarily, a bill from a telephone company is not created by any governmental agency or unit. Under the language of the federal Freedom of Information Act, 5 U.S.C. § 552(b)(5), which contains an exemption for interagency or intra-agency memoranda or letters and which is worded the same as § 10-618(b) of the Maryland Act, the courts have held that the exemption is limited to documents created by government agencies or agents, or by outside consultants called upon by a government agency “to assist it in internal decisionmaking.” County of Madison v. United States Dep’t of Justice, 641 F.2d 1036, 1040 (1st Cir.1981). See, e.g., Van Bourg, Allen, Weinberg & Roger v. NLRB, 751 F.2d 982, 985 (9th Cir.1985) (“exemption 5 by its terms applies only to internal agency documents or documents prepared by outsiders who have a formal relationship with the agency,” and does not apply to affidavits submitted to the NLRB by private parties in the course of an investigation); Ryan v. Department of Justice, 617 F.2d 781 (D.C.Cir.1980); Wu v. National Endowment for Humanities, 460 F.2d 1030 (5th Cir.1972), cert. denied, 410 U.S. 926, 93 S.Ct. 1352, 35 L.Ed.2d 586 (1973). A bill from a telephone service provider, charging for the listed telephone calls made, is not a document from a government agency or agency consultant employed to assist the agency in its decision-making function.
Moreover, bills from telephone companies and simple listings of the persons who have appointments with the Governor are not, under any ordinary meaning of the statutory language, letters or memoranda. For example, in Times Mirror Co. v. Superior Court, 53 Cal.3d 1325, 283 CaLRptr. 893, 813 P.2d 240 (1991), the Supreme Court of California construed, inter alia, an exemption from disclosure in the California Public Records Act for “Correspondence of and to the Governor or employees of the Governor’s office.” 53 Cal.3d at 1336-1337, 283 Cal.Rptr. at 893-894, 813 P.2d at 246. The Court rejected the Governor’s argument that “his calendars and schedules” constituted correspondence within the meaning of the exemption, pointing out that “correspondence” means “communication by letters.” 53 Cal.3rd at 1337, 283 Cal.Rptr. *553at 900, 813 P.2d at 247.12 Cf. Taylor v. Worrell Enterprises, 242 Va. 219, 409 S.E.2d 136 (1991) (dissenting opinion of three justices took the position that telephone records of the Governor’s office did not constitute “memoranda, working papers and correspondence” within an exemption in the Virginia Freedom of Information Act; one justice, in a concurring opinion, took the position that the records were within the exemption; three other justices, in the plurality opinion, based their decision on state constitutional grounds).
As discussed by this Court in Cranford v. Montgomery County, supra, 300 Md. at 771-776, 481 A.2d at 227-229, only certain types of letters and memoranda fall within the exemption in § 10-618(b). As a threshold matter, however, to come within the exemption a document must be an “inter-agency or intra-agency letter or memorandum.” Even if those terms are given a broad scope, the telephone bills and scheduling records here involved fail to meet this threshold test.
F.
Finally, the defendants rely on some cases from other jurisdictions which are based on statutory language or exemptions which are different from the language and exemptions of the Maryland Public Information Act.
A principal case relied on by the defendants is Times Mirror Co. v. Superior Court, supra, 53 Cal.3d 1325, 283 Cal.Rptr. 893, 813 P.2d 240. As pointed out by the Supreme Court of California in that opinion, the California Public Records Act contains “a ‘catchall’ exemption that permits the government agency to withhold a record if it can demonstrate that ‘ ... the public interest served by not making the record public clearly outweighs the public interest served by disclosure of the record.’’ ” 53 Cal.3d at 1338, 283 Cal.Rptr. at 895, 813 P.2d at 247-248, emphasis in original. The Supreme *554Court of California decided that the Governor’s “calendars and schedules” fell within this exemption, holding “that the public interest served by not disclosing the Governor’s appointment calendars and schedules clearly and substantially outweighs the public interest in their disclosure.” 53 Cal.3d at 1347, 283 Cal.Rptr. at 907, 813 P.2d at 254. See also Courier-Journal v. Jones, 895 S.W.2d 6 (Ky.App.1995), adopting the holding of the Times Mirror case in this regard.
Nevertheless, as the defendants acknowledge, the Maryland Public Information Act does not contain a general “catchall” public interest exemption. Instead, for a record to be exempt from disclosure because of the “public interest,” it must fall within one of the specific categories set forth in § 10-618. See Kirwan v. The Diamondback, supra, 352 Md. at 87-88, 721 A.2d at 202-203; Cranford v. Montgomery County, supra, 300 Md. at 770, 481 A.2d at 226-227. The records at issue in the present case fall within none of the categories delineated in § 10-618.13
The defendants also rely on Bureau of Nat. Affairs v. U.S. Dept. of Justice, 742 F.2d 1484, 1496 (D.C.Cir.1984), in which the court held that government officials’ telephone message slips and certain appointment calendars that “were not distributed to other employees, but were retained solely for the convenience of the individual officials,” did not constitute “agency records” within the meaning of the federal Freedom of Information Act. The court also held that “daily agendas,” indicating the schedule of the head of the Department of Justice’s Antitrust Division, which was circulated to certain members of his staff, were “agency records” and were disclosable. 742 F.2d at 1495. See also Washington Post v. U.S. *555Dept. of State, 632 F.Supp. 607 (D.D.C.1986) (records of the Secretary of State’s schedule are “agency records” and disc-losable under the federal statute).
The records which were held to be nondisclosable in the Bureau of Nat. Affairs case are dissimilar from the records involved in the case at bar. We do not have before us telephone message slips or an official’s appointment calendar which is not distributed to any other employees, and we express no opinion as to the disclosability of such material under Maryland law. In addition, the records held to be disclosable in the Bureau of Nat. Affairs case appear to be similar to the Governor’s scheduling records involved in the present case.
Nonetheless, the precise statutory issue in the Bureau of Nat. Affairs case, namely whether certain documents made by a governmental unit constitute “agency records,” does not arise under the Maryland Act. As discussed in Part II A of this opinion, supra, the federal statute applies only to “agency records.” In light of the legislative history underlying this term and the ease law construing it, not all records made by or received by a federal governmental unit or instrumentality constitute “agency records.” The Maryland Act, on the other hand, uses the term “public record” which includes “any documentary material” which is “made by a unit or instrumentality” of the government and “is in any form.... ” (Emphasis added). Consequently, cases deciding whether governmental documents are “agency records” within the meaning of the federal statute are not very pertinent in determining whether a governmental document is disclosable under the Maryland Public Information Act.
The defendants argue that the “privacy interests” of the public officials and the persons called would be invaded by a disclosure of the Governor’s office telephone records, and they cite, inter alia, the New Jersey Superior Court’s opinion in North Jersey Newspaper Co. v. Passaic County Bd. of Chosen Freeholders, 245 N.J.Super. 113, 584 A.2d 275 (1990), modified and remanded for further proceedings, North Jersey Newspa*556pers Co. v. Passaic County Bd. of Chosen Freeholders, 127 N.J. 9, 601 A.2d 693 (1992). The Superior Court in that case held that telephone billing records of public officials were public records under the New Jersey “Right-To-Know Law” but that they were exempt from disclosure because of “the privacy interests of elected officials in the telephone calls they make while performing their public duties.... ” 245 N. J.Super. at 121, 584 A.2d at 279. The Supreme Court of New Jersey, however, in modifying and remanding the case, held that the New Jersey “Right-To-Know Law” gave a right of access only to records “ ‘required by law to be made, maintained or kept,’ ” and that telephone bills did not fall within such category. 127 N.J. at 13-14, 601 A.2d at 695. The Maryland Public Information Act is not limited to public records which are required by law to be made, maintained, or kept, and thus the ultimate holding in the North Jersey Newspapers case has little relevance in cases under the Maryland Act. Furthermore, unlike the public information acts in some states, “the Maryland Public Information Act does not contain an exemption for particular cases whenever the disclosure of a record might cause an ‘unwarranted invasion of privacy.’ ” Kirwan v. The Diamondback, supra, 352 Md. at 89, 721 A.2d at 203.
V.
Section 10-615(1) of the Maryland Public Information Act, as previously noted, supra note 2, requires a custodian of a public record to deny inspection if “by law the record is privileged....”14 This Court has recognized that certain *557governmental documents need not be disclosed under the doctrine commonly known as “executive privilege” which is part of Maryland common law and which, to some extent, is rooted in the separation of powers principle set forth in Article 8 of the Maryland Declaration of Rights.15 Hamilton, Superintendent v. Verdow, supra, 287 Md. at 553-562, 414 A.2d at 920-924. See also Porter Hayden v. Bullinger, 350 Md. 452, 461, 713 A.2d 962, 966 (1998); Philip Morris v. Glendening, 349 Md. 660, 678, 709 A.2d 1230, 1239 (1998); Cranford v. Montgomery County, supra, 300 Md. at 773-774, 481 A.2d at 228-229.16 Consequently, if the records here at issue, or any part of them, are non-disclosable under the executive privilege doctrine, then such records or parts of records are exempt from disclosure under § 10-615(1) of the Maryland Public Information Act.
The doctrine of executive privilege, in addition to protecting military and diplomatic secrets, is chiefly designed to protect confidential advisory and deliberative communications to government officials. This Court in the Hamilton case thus explained (287 Md. at 558, 414 A.2d at 922):
*558“The necessity for some protection from disclosure clearly extends to confidential advisory and deliberative communications between officials and those who assist them in formulating and deciding upon future governmental action. A fundamental part of the decisional process is the analysis of different options and alternatives. Advisory communications, from a subordinate to a governmental officer, which examine and analyze these choices, are often essential to this process. The making of candid communications by the subordinate may well be hampered if their contents are expected to become public knowledge.”
After reviewing cases in the United States Supreme Court and other courts, we pointed out in Hamilton that
“the cases throughout the country, both federal and state, have recognized the doctrine of executive privilege which, in addition to state and military secrets, gives a measure of protection to the deliberative and mental processes of decision-makers.” 287 Md. at 561, 414 A.2d at 924.
The Court went on in Hamilton to hold that the privilege “is for the benefit of the public and not the governmental officials who claim the privilege” (287 Md. at 563, 414 A.2d at 924), that the privilege is not absolute, and that in “many situations the courts have engaged in a balancing process, weighing the need for confidentiality against the ... need for disclosure and the impact of nondisclosure upon the fair administration of justice.” 287 Md. at 563, 414 A.2d at 925. We also held in Hamilton that when a government official makes a formal claim of executive privilege for confidential communications “of an advisory or deliberative nature, there is a presumptive privilege, with the burden upon those seeking to compel disclosure.” Ibid.
Turning to factual documents as opposed to documents of an advisory or deliberative nature, we held in Hamilton that “[ojrdinarily, ‘memoranda consisting only of compiled factual material’” are disclosable, 287 Md. at 564, 414 A.2d at 925, quoting EPA v. Mink, 410 U.S. 73, 87, 93 S.Ct. 827, 836, 35 *559L.Ed.2d 119, 132 (1973). We recognized in Hamilton, 287 Md. at 564-565, 414 A.2d at 925-926, however, that
“material cannot always ‘easily be separated into fact finding and decision making categories,’ Boeing Airplane Company v. Coggeshall, supra, 280 F.2d at 662. Moreover, some factual material is entitled to a degree of protection under the privilege, although not to the same extent as opinions and recommendations. This would include facts obtained upon promises or understandings of confidentiality, investigative facts underlying and intertwined with opinions and advice, and facts the disclosure of which would impinge on the deliberative process. See, e.g., (relating to one type or another of such factual material): EPA v. Mink, supra, 410 U.S. at 92, 93 S.Ct. at 838; Mead Data Cent., Inc. v. U.S. Dept. of Air Force, 566 F.2d 242, 256-257, 260 (D.C.Cir.1977); Brockway v. Department of Air Force, 518 F.2d 1184, 1191-1194 (8th Cir.1975); Montrose Chemical Corporation of California v. Train, 491 F.2d 63, 66-71 (D.C.Cir.1974); J.H. Rutter Rex Manufacturing Co., Inc. v. N.L.R.B., 473 F.2d 223, 234-235 (5th Cir.1973), cert. denied, 414 U.S. 822, 94 S.Ct. 120, 38 L.Ed.2d 55 (1973); Freeman v. Seligson, 405 F.2d 1326, 1339-1340 (D.C.Cir.1968); Machin v. Zuckert, supra, [114 U.S.App.D.C. 335] 316 F.2d [336] at 339-340 [(1963)]; Rabbitt v. Department of Air Force, 401 F.Supp. 1206, 1209 (S.D.N.Y.1974). In these situations, the government’s asserted reasons for nondisclosure are weighed against the litigant’s need for discovery in light of the particular circumstances of each case. Frank-enhauser v. Rizzo, 59 F.R.D. 339, 342-346 (E.D.Pa.1973); O’Keefe v. Boeing Company, supra, 38 F.R.D. [329] at 334-336 [(S.D.N.Y.1965)].”
See also In re Sealed Case, 121 F.3d 729, 746-758 (D.C.Cir. 1997).
Although we noted, supra Part IV F, a distinction between the statutory exception we construe here and the California statutory exemption interpreted by the California Supreme Court in Times-Mirror Co. v. Superior Court, the California Court’s general observations regarding an analytical approach *560when considering assertions of executive privilege as to purely factual documents are worth mentioning (58 Cal.3d at 1341-1342, 283 Cal.Rptr. at 903, 813 P.2d at 250 (citations omitted)):
“In determining whether a document falls within the ... [deliberative process/executive privilege exemption], the federal courts' have also recognized ‘that it requires different treatment for materials reflecting deliberative or policy-making processes on the one hand, and purely factual, investigative matters on the other.’ The courts have readily acknowledged, however, that the fact/opinion dichotomy may be misleading, and have refused to apply it in a mechanical or unthinking manner. The privilege, as one appeals court has written, ‘is intended to protect the deliberative process of government and not just deliberative material.’ Accordingly, in some circumstances ‘the disclosure of even purely factual material may so expose the deliberative process ... that it must be deemed exempted.... ’ Decisions holding the exemption to be applicable even to ‘purely factual material’ are legion.
“In short, the courts’ focus ... is less on the nature of the records sought and more on the effect of the records’ release. The key question in every case is ‘whether the disclosure of materials would expose an agency’s decision-making process in such a way as to discourage candid discussion within the agency and thereby undermine the agency’s ability to perform its functions.’ Even if the content of a document is purely factual, it is nonetheless exempt from public scrutiny if it is ‘actually ... related to the process by which policies are formulated’ or ‘inextricably intertwined’ with ‘policy-making processes.’ ”
Although in the present case we need not go as far as the California Court in Times-Mirror did in applying the above analysis to its facts and legal context (because we are remanding this matter for further consideration), an example of how that court applied the analysis may be illustrative for the Circuit Court’s consideration on remand (53 Cal.3d at 1343, 283 Cal.Rptr. at 904, 813 P.2d at 251):
*561“Disclosing the identity of persons with whom the Governor has met and consulted [may be] the functional equivalent of revealing the substance or direction of the Governor’s judgment and mental processes; such information [may] indicate which interests or individuals he deemed to be of significance with respect to critical issues of the moment.”
In light of the above-summarized principles, it is clear that the trial court correctly rejected the defendants’ blanket claim of executive privilege encompassing all of the telephone and scheduling records here involved. Bills from telephone service providers and listings of scheduled appointments are not communications “of an advisory or deliberative nature,” Hamilton, 287 Md. at 563, 414 A.2d at 925. Accordingly, under Hamilton, “a presumptive privilege” does not attach to them upon the claim of executive privilege, and the burden was upon the defendants to establish that the records were privileged. Ibid.
Considering the defendants’ assertion of an executive privilege exemption on an item-by-item basis requires application of the balancing test discussed in Hamilton, 287 Md. at 564-567, 414 A.2d at 925-927. Although the weight in the Hamilton balancing test given the request of the person seeking the governmental record was grounded in the discovery rights of a party in pre-existing litigation,17 the initial weight accorded the plaintiffs request in the balancing test in the present case has been pre-determined legislatively by the Maryland Public Information Act’s general, but explicit, disposition favoring disclosure. Because the records at issue here reflect only factual material, and there yet has been no contention made that they “include facts obtained upon prom*562ises or understandings of confidentiality, [or] investigative facts underlying and intertwined with opinions and advice,” Hamilton, 287 Md. at 565, 414 A.2d at 926,18 an in camera review and balancing test application are appropriate. See § 10 — 623(c)(2). As noted earlier, the defendants’ assertion of a blanket executive privilege, with its attendant presumption in favor of non-disclosure, fails because the records sought to be protected patently do not represent the content of confidential communications of an advisory or deliberative nature. Hamilton, 287 Md. at 563, 414 A.2d at 925. Rather, the defendants’ claimed exemptions seek to protect records from which such content may be inferred or discovered. Such a basis for the claimed exemption falls at best at the fringes or perimeter of potentially protectable records for which an in camera review and balancing test are necessary to assure proper vindication of the competing interests.
The defendants assert that the telephone and scheduling records constitute “facts the disclosure of which would impinge on the deliberative process.” Hamilton, 287 Md. at 565, 414 A.2d at 926. They make various arguments in support of this assertion.
First, the defendants seem to argue that disclosure of the names of persons with whom the Governor met or who were telephoned by the Governor, Mr. Riddick, or Ms. Smith-Bauk, would violate the privacy rights of those officials and the persons with whom they spoke, and would make persons reluctant in the future to give the Governor advice since their names might be revealed. (Petitioners’ brief at 20-22, 28). *563We observe that the executive privilege doctrine, as recognized in Hamilton and the cases there cited, is not for the benefit of the public officials or those giving advice to the public officials, but “is for the benefit of the public,” Hamilton, 287 Md. at 563, 414 A.2d at 924. That is not necessarily dispositive of defendants’ claim here.
Furthermore, although the substance of what an adviser tells a public official may be entitled to some protection under the executive privilege doctrine, nothing in Hamilton, or the cases there relied upon, suggests that executive privilege permits nondisclosure of every adviser’s name. The Hamilton case involved a confidential report from the Governor’s Chief Legislative Officer and Legal Counsel which contained opinions and recommendations for the Governor’s use, and we held that the report, or parts of the report, fell within the doctrine of executive privilege and might not have to be disclosed. Giving free range to the defendants’ argument in the case at bar, a Governor could keep secret the name of his Chief Legislative Officer and Legal Counsel, or the names of some other staff members who advise him. We do not believe that the privilege for confidential communications of an advisory or deliberative nature extends so far as to keep secret the names of all advisers.
The defendants have yet to present evidence supporting their assertion that the mere public disclosure of the Governor’s Office telephone bills or of the Governor’s prior appointments will have a chilling effect upon the willingness of persons to render advice to the Governor. And, as stated above, we recognize no general executive privilege for public officials’ office telephone bills or scheduling records. Nevertheless, this case is being remanded to the Circuit Court for further proceedings. Our opinion does not preclude the defendants from attempting to show the trial court, on remand, that because of identified special circumstances, disclosure of a specific telephone number, or certain specific numbers, or disclosure of specific scheduling records, will interfere with the deliberative process in the Governor’s Office. If the trial *564court concludes that the defendants have made a sufficient showing as to any specific telephone call or any specific appointment, it should redact the records accordingly.
The defendants argue that some of the telephone calls and meetings with the Governor relate to economic development projects and efforts “to attract businesses to locate headquarters or operations in Maryland. * * * With access on demand to the Governor’s telephone records, reporters easily could identify a series- of telephone calls to a particular company, inferring negotiation activity. * * * [T]he simple contact by a reporter to such a company could scare away that potential source of economic development.” (Petitioners’ brief at 28-24). The defendants make a similar argument with regard to recruiting persons for high level state employment such as a presidency of a state university. At the time the Post brought this suit in December 1997, it was seeking telephone bills and scheduling records for a six-month period from February 1, 1996, through July 31, 1996. In other words, the Post was seeking records of telephone calls and appointments for one and a half to two years in the past. The records sought are now four years old. Present disclosure of four-year-old telephone or scheduling records may or may not upset current economic development negotiations or recruitment negotiations which might fail if they are not kept confidential. Current disclosure of telephone numbers or meetings relative to such negotiations that have expired or been consummated may or may not have a sufficiently inhibitory effect on the Governor’s ability to maintain similar negotiations in the future. Our decision in this case is without prejudice to the defendants’ making a showing to the Circuit Court on remand that a particular four-year-old telephone number or scheduling record either is still involved in current confidential economic development or recruitment negotiations and that present disclosure of that number or record will interfere with the negotiations, or that such disclosure is likely to interfere substantially with the Governor’s ability to have such negotiations in the future.
*565To reiterate, we reject the defendants’ argument that the factual records here involved are generally subject to executive privilege and, therefore, are nondisclosable under § 10-615(1) of the Act. Nonetheless, if the defendants upon remand are able to demonstrate that certain specific records or portions thereof are privileged under the principles set forth in Hamilton, 287 Md. at 564-565, 414 A.2d at 925-926, and in this opinion, the Circuit Court should permit redactions of that material.
JUDGMENT OF THE CIRCUIT COURT FOR ANNE ARUNDEL COUNTY VACATED, AND CASE REMANDED TO THAT COURT FOR FURTHER PROCEEDINGS CONSISTENT WITH THIS OPINION. PETITIONERS TO PAY TWO THIRDS OF THE COSTS AND RESPONDENT TO PAY ONE THIRD OF THE COSTS.
BELL, C.J., RAKER and CATHELL, JJ., dissent.
. Unless otherwise indicated, all statutory references are to the Maryland Public Information Act, §§ 10-611 through 10-630 of the State Government Article, hereafter sometimes referred to simply as "the Act.”
. Section 10-618(b) of the Maryland Public Information Act provides as follows:
"(b) Interagency and intra-agency documents. — A custodian may deny inspection of any part of an interagency or intra-agency letter or memorandum that would not be available by law to a private party in litigation with the unit.”
In addition, § 10-615 provides in pertinent part that "[a] custodian shall deny inspection of a public record or any part of a public record if: (1) by law, the public record is privileged or confidential....”
. Section 10-611(g) of the Act defines “public record” as "the original or any copy of any documentary material that:
"(i) is made by a unit or instrumentality of the State government or of a political subdivision or received by the unit or instrumentality in connection with the transaction of public business; and
(ii) is in any form, including ... a computerized record....”
. The Governor’s appointment or scheduling records consisted of four types of documents: (1) a handwritten appointment book; (2) an electronic "working” schedule; (3) the last-edited version of the working schedule; and (4) the Governor’s personal daily schedule, printed for him on a note card. The handwritten appointment book is created by Ms. Joanne Trumbule, the Governor’s Director of Scheduling, and her immediate staff, by penciling in the many requests for meetings with the Governor. This book also includes the Governor’s personal appointments and family engagements. The same group of people then prepare the electronic working schedule, which includes "the time, location, persons attending, and staff person responsible for the designated activity.” Some entries also include the subject matter of the appointment or event. Personal activities are also noted on the working schedule. The working schedule is distributed by electronic mail to the Governor’s staff for input, and then is refined further, either by canceling appointments, scheduling new appointments, or editing the specific information on already-existing appointments. The "last-edited version” of the working schedule is then used to create the Governor’s personal daily schedule, which is prepared by Ms. Trumbule or an assistant late in the afternoon of the preceding day. The personal daily schedule is distributed to the Governor, the Maryland State troopers assigned to protection of the Governor, and a small group of staff members.
. Maryland Rule 8-131(a) states as follows:
"Rule 8-131. Scope of review.
(a) Generally. The issues of jurisdiction of the trial court over the subject matter and, unless waived under Rule 2-322, over a person may be raised in and decided by the appellate court whether or not raised in and decided by the trial court. Ordinarily, the appellate court will not decide any other issue unless it plainly appears by the record to have been raised in or decided by the trial court, but the Court may decide such an issue if necessary or desirable to guide the trial court or to avoid the expense and delay of another appeal.”
Nevertheless, because the second sentence of the above-quoted rule begins with the word "[ojrdinarily,” both "the Court of Special Appeals and this Court each have independent discretion’ to excuse the failure of a party to preserve an issue for appellate review.” Moosavi v. State, 355 Md. 651, 661, 736 A.2d 285, 290 (1999), quoting Squire v. State, 280 Md. 132, 134-135, 368 A.2d 1019, 1020 (1977). See Gindes v. Khan, 346 Md. 143, 151, 695 A.2d 163, 167 (1997) ("Rule 8-131(a) is not absolute.... Under this rule the Court has discretion,, which we have exercised on occasion, to consider an issue raised for the first time on appeal”).
*533Moreover, we shall be remanding this case to the Circuit Court for further proceedings, and the issue of the applicability of the Act to the defendants is a threshold issue of law. Thus, it is the type of issue contemplated by the final clause of Rule 8-131(a). In sum, we shall exercise our discretion to consider the issue.
. Mr. Kissinger was Assistant to the President for National Security Affairs from January 1969 until November 1975, and was Secretary of State from September 1973 until January 20, 1977.
. For an account of the history and purpose of this provision, see Gallagher v. Bd. of Sup'rs of Elections, 219 Md. 192, 202-203, 148 A.2d 390, 396 (1959).
. The defendants in the Circuit Court also ‘‘identified for redaction all personal calls placed by any one of the three officials at issue from their office locations,” arguing that because a personal "call does not involve State business, the record of the call should not be considered a public record” (petitioners’ brief at 46-47). We do not agree totally. Although the content of such calls may be private, the bill from a telephone company to the State, for calls made from state offices by state officials or employees on state telephones during their working hours, clearly falls within the definition of "public record” in the Act. It is a document received by a unit of government, and, in our view, it is "in connection with the transaction of public business.” Although employees must occasionally make personal telephone calls from their employers' phones during working hours, the frequency of and the amount of time spent on such calls is clearly a matter of legitimate concern to the employer. This is true regardless of whether there exists a reimbursement record. The taxpayers and citizens of Maryland, as the employers of state officials and employees, have a legitimate interest in the frequency and length of personal telephone calls made on state office telephones. That interest may be vindicated, however, by disclosure of the aggregated totals of time spent and charges incurred on calls devoted to personal business versus public business. Thus, absent evidence of abuse, this degree of disclosure would be sufficient.
. In the Circuit Court, in their motion for summary judgment, the defendants also relied upon the exemption for "financial information” in § 10 — 617(f)- They have not relied upon this exemption on appeal and thus have abandoned any argument based on § 10-617(f). With regard to the meaning and scope of the "financial information” exemption, see Kirwan v. The Diamondback, 352 Md. 74, 84-87, 721 A.2d 196, 201-202 (1998).
. The material submitted to the Circuit Court for in camera review actually identified the recipients where we have employed blanks.
. Again, the material submitted to the court below in camera actually identified the person with whom the Governor was meeting and the particular position involved.
. As discussed later, the Supreme Court of California in the Times Mirror case did hold that the Governor’s calendars and schedules were exempt from disclosure under a different exemption in the California statute.
. There is also a provision in the Maryland Act, in § 10-619, authorizing a temporary denial of inspection based on "substantial injury to the public interest." Section 10-619 specifies a particular procedure which must be followed by the custodian who temporarily denies inspection based on the public interest. Section 10-619 was not invoked in the present case, and the defendants do not rely upon that section. See Cranford v. Montgomery County, supra, 300 Md. at 776, 481 A.2d at 229-230.
. Section 10-615 in its entirety states:
“§ 10-615. Required denials — In general.
A custodian shall deny inspection of a public record or any part of a public record if:
(1) by law, the public record is privileged or confidential; or
(2) the inspection would be contrary to:
(i) a State statute;
(ii) a federal statute or a regulation that is issued under the statute and has the force of law.
(iii) the rules adopted by the Court of Appeals; or
*557(iv) an order of a court of record.”
. Article 8 of the Maryland Declaration of Rights provides:
"That the Legislative, Executive and Judicial powers of Government ought to be forever separate and distinct from each other; and no person exercising the functions of one of said Departments shall assume or discharge the duties of any other.”
. As pointed out in Hamilton, Superintendent v. Verdow, supra, 287 Md. at 553-554 n. 3, 414 A.2d at 920 n. 3, the name “executive privilege” is "an overly narrow term, because the privilege extends beyond the executive branch of government. As it has roots in the constitutional doctrine of separation of powers, a similar privilege extends to the judicial and legislative branches as well.”
The Hamilton case, as well as the Cranford case, 300 Md. at 772, 481 A.2d at 227-228, also pointed out that the same overall privilege has gone by other names, such as the privilege for “governmental secrets,” the "state secret” privilege, the "official information” privilege, the "deliberative process” privilege, the "pre-decisional” privilege, etc. Nevertheless, the term "executive privilege” seems to be the one most often used by lawyers and courts.
. Hamilton reached us upon certified questions of law from the United States District Court for the District of Maryland arising from a civil suit in the District Court brought by the personal representative of the estate of a murder victim against the superintendent of the Spring Grove State Hospital and two of its staff psychiatrists for the alleged negligent release of the killer. 287 Md. at 546-547, 414 A.2d at 916-917. Thus, the plaintiff’s need for the governmental record in that case was balanced against the assertion of executive privilege.
. The defendants, while not asserting that any of the particular records at issue in this case involved promises of confidentiality, do contend as a general matter that the Governor and his staff "must have the freedom to contact individuals with the assurance of confidentiality.” (Petitioners’ brief at 25). If, upon remand, the defendants make a showing, by affidavit or otherwise, that the recipient of a particular telephone call, or a person who met with the Governor, was given assurance that the fact of the telephone call or the fact of the meeting would be kept confidential, then under the Hamilton opinion such number or the person’s name in the scheduling record should be redacted.