The party ratio in the Senate standing committees is the proportional number of members of each party caucus assigned to each committee. Determining sizes, ratios, and committee assignments are among the first actions taken after a general election and at the beginning of a Congress. The standing rules of the Senate are silent on the subject of committee party ratios; the apportionment of committee seats results from discussions beginning in the early organization period between majority and minority party leadership. In general, the result of these discussions has been to apportion total committee seats to the majority and minority parties in a manner that corresponds to the party strength in the full chamber. A finding of this report indicates that the majority party ratios on committees roughly approximate the majority party strength in the Senate chamber, regardless of which party has been in control. This report shows Senate committee party ratios for 18 Congresses, covering the period of the 98 th Congress (1983-1985) through the beginning of the 115 th Congress (2017-2019). In addition to the standing committees, data on permanent select committees with legislative jurisdiction are also included. An additional table ( Table 1 ) provides a comparison of majority party strength in the Senate chamber and total committee seats. The data presented in this report are drawn from the official committee assignment lists issued by the Secretary of the Senate, after assignments were made in each Congress. Data for the 107 th Congress reflect committee ratios established after the Senate reorganization in June 2001 as a result of the end of a power-sharing agreement. For the 99 th through 115 th Congresses, data on overall party strength in the Senate for each Congress were taken from the same lists. Overall party strength data for the 98 th Congress were taken from the Congressional Directory . The data in this report are from the earliest available complete information of each Congress contained in these two primary documents. Table 1 shows a comparison of majority party strength in the Senate chamber with total majority committee seats for the 98 th Congress (1983-1985) through the 115 th Congress (2017-2019). Unfilled seats on committees (if so noted in the Secretaries' lists or the Congressional Directory ) are counted in individual and overall committee totals for consistency. Tables 2- 19 show the following for each of the 18 Congresses examined, by majority, minority, and Independents (where present) Senate party breakdown and majority margin; total committee seats, majority and minority committee seats, and majority margin; the standing and select committees (with legislative jurisdiction) as established and named in each Congress; committee seats allocated to the majority and minority parties, including Independents (where present), for each committee; and majority-minority seat margin for each committee.

Summary:
The party ratio in the Senate standing committees is the proportional number of members of each party caucus assigned to each committee. Determining committee sizes, ratios, and assignments are among the first actions taken after a general election and at the beginning of a Congress. The standing rules of the Senate are silent on the subject of committee party ratios. The apportionment of committee seats results from discussions between majority and minority party leadership. In general, it has been the practice of the Senate to apportion committee seats to the majority and minority parties in a manner that corresponds closely to the party strength in the full chamber. Findings from this study indicate that the majority party ratios on committees roughly approximate the majority party strength in the Senate chamber, regardless of which party has been in control. This report shows Senate committee party ratios for 18 Congresses, covering the period of the 98th Congress (1983-1985) through April 2017, the first part of the 115th Congress (2017-2019). Table 1 shows a comparison of majority party strength in the Senate chamber with total majority committee seats for the 98th Congress through the beginning of the 115th Congress. Unfilled seats on committees (if so noted in the Secretary of the Senate's lists or the Congressional Directory) are counted in individual and overall committee totals for consistency. Tables 2-19 show the following for each of the 18 Congresses examined, by majority, minority, and Independents (where present) Senate party breakdown and majority margin; total committee seats, majority and minority committee seats, and majority margin; the standing and select committees (with legislative jurisdiction) as established and named in each Congress; committee seats allocated to the majority and minority parties, including Independents (where present), for each committee; and majority-minority seat margin for each committee. The committee ratios data for the 99th through 115th Congresses are taken from the official committee lists for each Congress issued by the Secretary of the Senate; the Congressional Directory is the source for the 98th Congress. The earliest editions of these primary documents are generally the sources for the data, although anomalies in some Congresses, such as a delay in seating a Senator due to a contested election, sometimes necessitated using later versions of the publications. Party strength in each Congress reflects numbers found in the Secretary's lists and the Congressional Directory. Different versions of the Secretary's list and the Congressional Directory, or the use of alternate sources or methodologies, could yield different results.