There are no authoritative, comprehensive statistics on the amount of oversight or even the number of specialized investigations throughout the history of the Congress. This absence is, in part, because scholars have disagreed as to what constitutes oversight and, therefore, how it should be measured as well as the difficulty and high research costs of quantifying congressional activities.32

Nonetheless, some statistics -- albeit lacking completeness and comparative value over time -- are available. Despite their weaknesses, these data tend to show that Congress has increased its oversight activity over its history, particularly over the past three decades.

Congressional investigations, as a highly visible component of oversight, appear to have increased over time. According to one source, for instance, about 30 investigations were conducted by Congress between 1792 and 1814.33 It was not until the administration of John Quincy Adams (1825-1829), however, that congressional investigating committees had become a part of the political machinery of the time.34 One count determined that by 1928, moreover, 330 investigations had been conducted by congressional committees and subcommittees, with double that number occurring between 1933 and 1958.35 A recent study of the post-World War II era, furthermore, identified 31 high-publicity, high-profile investigations that stood out from the many other more routine or less visible congressional efforts.36

The amount of oversight conducted by Congress has increased markedly from the early 1960s to the early 1980s, at least as measured by number of days of congressional hearings devoted to the function. Data compiled by Joel Aberbach in Keeping a Watchful Eye: The Politics of Congressional Oversight reveal that such hearings and meetings increased by 207 percent over a 22-year period.37

In 1961 -- during a time when oversight was considered ``Congress' neglected function''38 N -- it constituted only 8.2 percent of the total number of days of hearings and meetings; in 1983, by contrast, oversight accounted for 25.2 percent of the total.39 Table 2, extracted from Aberbach's study,40 details the growth over these two decades.

Table 2. Hearings and Meetings of Congressional Committees,
January 1-July4, 1961-83a
Total daysb
Oversight daysc
Oversight as percent of total
Percent change
a Source: Data based on the description in the Daily Digest of the Congressional Record. Hearings and meetings held by Appropriations, Rules, Administration, and Joint Committees are excluded. The 1979 data are missing because they were not coded.
b Total days mean a count of the total number of days that committee met for any purpose during the time covered.
c Oversight days means days committees devoted to primary-purpose oversight. Day is shorthand for a hearing or meeting. The typical event lasted two or three hours on a given date.
d Large number of oversight days occurs mostly because of one unusually long series of hearings (33 days) on a single topic.

Notwithstanding this feature, the percentage of days devoted to oversight actually declined early in the Nixon Administration, even though divided party government continued in effect. (Later in the Nixon Administration, as would be expected, the amount of oversight escalated as his Presidency was embroiled in Watergate, which led to criminal investigations of the President and top White House staff, to high-visibility congressional inquiries, including impeachment proceedings in the House, and eventually to his resignation.) Furthermore, the Carter Administration in 1977, when the Presidency and Congress were controlled by the same political party, witnessed an increase in the number of days of oversight hearings, although the percentage was roughly the same as under his predecessor.

This all suggests that partisanship is but one of a number of factors affecting the amount and rate of oversight and that divided party government is not a sufficient condition alone for increased oversight.41 A corollary is that high amounts and rates of oversight may occur even during periods of unified party control. David Mayhew's study of the impact of divided party government tends to confirm these hypotheses. Based on a survey of 31 high-publicity investigations from 1946-1990, Mayhew found that Congress was as likely to conduct such investigations when there was unified party government as when there was divided party government.42


32 See especially Aberbach, Keeping a Watchful Eye, pp. 217-219, and Kaiser, ``Congressional Oversight of the Presidency,'' pp. 80-81.
33 James H. Hutson, To Make All Laws: The Congress of the United States, 1789-1989, Washington, Library of Congress, 1989. p. 58.
34 Ibid.
35 Ibid.
36 Mayhew, Divided We Govern, pp. 8-34.
37 Aberbach, Keeping a Watchful Eye, p. 35. Even these statistics, which show such a marked increase, probably underestimate and undercount the amount of oversight for several reasons. As the author recognizes (ibid., pp. 35-36 and 231), the data do not include hearings by the House and Senate Appropriations Committee. These efforts, however, can include a substantial amount of oversight as the panels look into the agencies' on-going operations and activities.
A second reason for the undercount is that the data base is derived from the Daily Digest in the Congressional Record. Although the Daily Digest offers a useful sketch of committee hearings and meetings, it understates committee activity in general and underestimates oversight activity in particular. For instance, confirmation hearings would not be counted as oversight even though (on rare occasion) they may be heavily oriented to that purpose. An example of this occurred with the two confirmation proceedings of Robert M. Gates to be Director of Central Intelligence; these were conducted by the Senate Select Committee on Intelligence in 1987, in the immediate aftermath of the Iran-contra affair, when he withdrew his nomination, and again in 1991, when he was confirmed. Also, annual authorization hearings may be described in the Daily Digest as focusing on future and projected programs and operations, when, in fact, these efforts may delve into agency activities over the recent past.
38 John Bibby, ``Oversight: Congress' Neglected Function.'' In Melvin Laird, editor, Republican Papers, New York, Praeger, 1968.
39 Aberbach, Keeping a Watchful Eye, p. 35.
40 Ibid.
41 For elaboration on the multiple factors involved, see Aberbach, Keeping a Watchful Eye, pp. 19-79; Ogul, Congress Oversees the Bureaucracy, pp. 3-23; and Frederick M. Kaiser, ``Oversight of Foreign Policy: The U.S. House Committee on International Relations,'' Legislative Studies Quarterly, vol. 2, August 1977. pp. 296-307.
42 Mayhew, Divided We Govern, pp. 3-4 and 8-34. Mayhew actually contends that his study takes exception to earlier interpretations which he reads as arguing that partisan division between the President and Congress is a, if not the, principal inducement to oversight. Ibid., p. 3.
These other studies, however, point to such partisan division as only one factor -- adding only one incentive and providing only a tendency -- in stimulating oversight endeavors, by comparison to periods of unified party government. The many other factors inducing congressional oversight have little if anything to do with a partisan split between the branches. These include: subject matter which is not overly complex or technical, controversy surrounding a policy, factionalism within a political party, lack of confidence in administrators or personal antipathy to them, poor treatment of legislators by the officials of the agency being overseen, high Member priority for and competence in oversight or the issue area, adequate resources and funding to conduct an inquiry, high visibility and political payoff for the effort, decentralized committee structure and/or a supportive committee chairman. For a summary of these and still other factors, see Ogul, Congress Oversees the Bureaucracy, pp. 21-22.

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