Congressional Careers: Service Tenure and
Patterns of Member Service, 1789-2011
Matthew Eric Glassman
Analyst on the Congress
Erin Hemlin
Research Associate
Amber Hope Wilhelm
Graphics Specialist
January 7, 2011
Congressional Research Service
7-5700
www.crs.gov
R41545
CRS Report for Congress
P
repared for Members and Committees of Congress
Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Summary
The average service tenure of members of the Senate and House of Representatives has varied
substantially since 1789. This report presents data on member tenure and a historical analysis of
tenure trends.
During the 19th century, the average service of Representatives and Senators remained roughly
constant, with little or no change over time; average years of service was slightly higher for the
first half of the century than during the second. During the late 19th and through the 20th century,
the average years of service for Senators steadily increased, from an average of just under five
years in the early 1880s to an average of just over 13 years in recent Congresses. Similarly, the
average years of service of Representatives increased from just over four years in the first two
Congresses of the 20th century to an average of approximately 10 years in the three most recent
Congresses.
The average years of service for members of the 112th Congress, as of January 5, 2011, when the
Congress convened, was 9.8 years for the House and 11.4 years for the Senate. The average years
of service for members of the 111th Congress, as of January 3, 2009, when the Congress
convened, was 10.3 years for the House and 13.4 years for the Senate.
Two underlying factors appear to influence variation over time in the average years of service for
members of Congresses: the decision of sitting members whether or not to seek election to the
next Congress, and the success rate of members who seek election to the next Congress. In
addition, short-term variation in average service is affected by the individual service tenures of
members who do not return for the following Congress.
Observed increases in the proportion of members seeking re-election and decreases in the
proportion of members defeated for re-election conform with previous scholarly assessments of
congressional history, which largely conclude that during the early history of Congress, turnover
in membership was frequent and resignations were commonplace, and that during the 20th
century, congressional careers lengthened as turnover decreased and Congress became more
professionalized.
The report also examines two further issues related to member tenure. First, the distribution of
member service that underlies the aggregate chamber averages is examined. Although the average
service tenure of members has increased, more than half of Representatives and nearly half of
Senators in recent Congresses have served eight years or less. Second, the report analyzes
historical trends in the percentage of members who have served in both chambers. While only a
small and declining proportion of Representatives have historically had previous Senate
experience, throughout history a sizeable percentage of Senators have previously served in the
House.
For information on the number of freshmen elected to Congress, refer to CRS Report R41283,
First-Term Members of the House of Representatives and Senate, 64th – 111th Congresses, by
Jennifer E. Manning and R. Eric Petersen.
This report will be updated at the beginning of each Congress.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Contents
Introduction ................................................................................................................................ 1
Methodology............................................................................................................................... 1
Data...................................................................................................................................... 1
Summary Statistics................................................................................................................ 2
Average Service Tenure............................................................................................................... 2
House of Representatives ...................................................................................................... 3
Senate ................................................................................................................................... 4
Analysis................................................................................................................................ 4
The Rate of Members Seeking Re-Election ..................................................................... 4
Re-election Success Rate................................................................................................. 5
Discussion ...................................................................................................................... 6
Patterns of Congressional Service ............................................................................................... 8
Distribution of Service Experience ........................................................................................ 8
Cross-Chamber Experience ................................................................................................... 9
Concluding Observations .......................................................................................................... 12
Figures
Figure 1. Average Service Tenure, Senators and Representatives ................................................. 3
Figure 2. Percentage of Representatives Who Did Not Seek Re-Election ..................................... 5
Figure 3. Percentage of Representatives Defeated for Re-Election ............................................... 6
Figure 4. Distribution of Representative Service Tenure .............................................................. 8
Figure 5. Distribution of Senator Service Tenure ......................................................................... 9
Figure 6. Percentage of Senators With Previous Service in the House ........................................ 10
Figure 7. Average Years of House Service Among Senators ....................................................... 11
Figure 8. Percentage of Representatives with Previous Service in the Senate ............................. 12
Contacts
Author Contact Information ...................................................................................................... 13
Congressional Research Service
Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Introduction
This report presents data on member tenure and a historical analysis of tenure trends. During the
19th century, the average service of Representatives and Senators remained roughly constant, with
little or no change over time; average years of service was slightly higher for the first half of the
century than during the second. During the late 19th and through the 20th century, the average
years of service for Senators and Representatives steadily increased.
Two underlying factors appear to influence variation over time in the average years of service for
members of Congresses: the decision of sitting members whether or not to seek election to the
next Congress, and the success rate of members who seek election to the next Congress. In
addition, short-term variation in average service is affected by the individual service tenures of
members who do not return for the following Congress.
The findings presented here conform with scholarly assessments of congressional history, which
largely conclude that during the early history of Congress, turnover in membership was frequent
and resignations were commonplace. Most lawmakers in the 18th and early 19th centuries can be
characterized as “citizen legislators,” holding full-time non-political employment and serving in
Congress on a part-time basis for a short number of years. During the 20th century, congressional
careers lengthened as turnover decreased and Congress became more professionalized.
The report also examines two further issues related to member tenure: the distribution of member
service that underlies the aggregate chamber averages and historical trends in the percentage of
members who have served in both chambers. Although the average service tenure of members has
increased, more than half of Representatives and nearly half of Senators in recent Congresses
have served eight years or less. While only a small and declining proportion of Representatives
have historically had previous Senate experience, throughout history a sizeable percentage of
Senators have previously served in the House.
Methodology
Data
The data presented here come from three sources. For the 1st through 104th Congresses, data were
drawn from the Roster of United States Congressional Officeholders and Biographical
Characteristics of Members of the United States Congress, 1789-1996.1 Data for the 105th through
111th Congresses were compiled from the Congressional Directory.2 Data for the 112th Congress
1 Inter-university Consortium for Political and Social Research, and Carroll McKibbin. Roster of United States
Congressional Officeholders and Biographical Characteristics of Members of the United States Congress, 1789-1996:
Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI: Inter-university for Political and Social Research
[producer and distributor], 1997.
2 U.S. Congress, Joint Committee on Printing, Official Congressional Directory, 111th Congress, S. Pub 111-14, 111th
Cong., 1st sess. (Washington: GPO, 2009); U.S. Congress, Joint Committee on Printing, Official Congressional
Directory, 110th Congress, S. Pub 110-13, 110th Cong., 1st sess. (Washington: GPO, 2007); U.S. Congress, Joint
Committee on Printing, Official Congressional Directory, 109th Congress, S. Pub 109-12, 109th Cong., 1st sess.
(Washington: GPO, 2006); U.S. Congress, Joint Committee on Printing, Official Congressional Directory, 110th
Congress, S. Pub 108-18, 108th Cong., 1st sess. (Washington: GPO, 2003); U.S. Congress, Joint Committee on Printing,
(continued...)
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
come from the Clerk of the House and CQ Press’s Guide to the New Congress.3 All three sources
of data were combined into one dataset.4
Chamber service and total congressional service were recorded for each member of each
Congress, as of the first day of Congress. Freshmen members in each house are counted as having
no service (zero years), and changes in membership during a Congress were not taken into
account. From these individual data, aggregate statistics were derived for each Congress.
Summary Statistics
The database consists of a total of 47,239 cases. The average service of Representatives was
highest in the 102nd, 110th, and 111th Congresses, where members had an average of 10.3 years of
House service, or just over five terms. The highest average service of Senators occurred in the
111th Congress, where Senators had an average of 13.4 years of service, slightly more than two
terms. For both the House and Senate, the Congress with the least average years of experience
was the 1st, as all Senators and Representatives necessarily had zero years of experience upon
arrival. In the last 50 years, the Congress with the lowest average years of service among
Representatives and Senators was the 97th Congress (1981-1982), in which Representatives had
an average of 7.4 years of service in the House (slightly more than 3.5 terms) and Senators had an
average of 7.5 years of service in the Senate (1.25 terms).
John Dingell Jr. is the longest serving Representative, with 56 years of service at the beginning of
the 112th Congress (2011-2013). The longest serving Senator was Robert Byrd, who had 50 years
of service in the Senate at the beginning of the 111th Congress. As of the beginning of the 111th
Congress, Byrd also had the most cumulative congressional service, with an additional six years
of House service.
Average Service Tenure
For each Congress, the average years of service was calculated for each chamber, as of the first
day of the Congress. Figure 1 graphically plots the data from the 1st to 112th Congress.
(...continued)
Official Congressional Directory, 107th Congress, S. Pub 107-20, 107th Cong., 1st sess. (Washington: GPO, 2001); U.S.
Congress, Joint Committee on Printing, Official Congressional Directory, 106th Congress, S. Pub 106-21, 106th Cong.,
1st sess. (Washington: GPO, 1999); U.S. Congress, Joint Committee on Printing, Official Congressional Directory,
105th Congress, S. Pub 105-20, 105th Cong., 1st sess. (Washington: GPO, 1997).
3 U.S. Congress, House, Office of the Clerk, 112th Congress Members-Elect, available at http://clerk.house.gov/
member_info/112-members-elect.pdf; CQ Roll Call, Guide to the New Congress, 112th Congress, November 4, 2010,
available at http://innovation.cq.com/newmember/2010elexnguide.pdf.
4 Each case represents a Member-Congress. For example, a Member who served for 8 terms would have eight cases in
the dataset, one for each Congress, with each case reflecting his service record as of the first day of that Congress.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Figure 1. Average Service Tenure, Senators and Representatives
1st through 112th Congress (1789-2013)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
House of Representatives
As shown in Figure 1, during the 19th century, the average service of Representatives remained
roughly constant, with only 12 Congresses having an average service greater than 3.0 years and
just one Congress having an average service less than 1.5 years.5 Additionally, there appears to be
little or no change over time; average years of service was slightly higher for the first half of the
century than during the second. During the 20th century, the average years of service for
Representatives steadily increased, from an average of just over four years in the first two
Congresses of the century to an average of approximately 10 years in the three most recent
Congresses. Average years of service peaked at 10.3 years of service in the 102nd Congress (1991-
1992), and was also 10.3 years of service in the 110th and 111th Congresses (2007-2008 and 2009-
5 The data on service tenures of the earliest Congresses is purposely excluded from this analysis. Average service
tenure in the 18th century Congresses (1st through 6th) is artificially constrained by the inability of anyone to have began
their service prior to the 1st Congress. While this artificial constraint is theoretically active well into the early 19th
century (for example, no member of the 11th Congress could have more than 20 years of prior service), it is a practical
analytical constraint only for the first 5 or 7 Congresses. After that, aggregate service tenures stabilize in line with
observed trends during the remainder of the first half of the 19th century. Furthermore, average tenure decreases in the
House in the 5th and 8th Congress and in the 7th and 9th Senate, which indicates that while the artificial constraint may
be theoretically suppressing the aggregate service average, it is no longer a dominant practical factor.
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2010). At the start of the 112th Congress, the average years of service for Representatives was 9.8
years.
Senate
Historically, the average years of service among Senators has been similar to that of
Representatives, with little variation during the first 100 years after the founding, followed by a
steady increase over the next 100 years. As shown in Figure 1, during the first 30 years of the
union, the average service of Senators tracked closely to the average service of Representatives.
After an increase during three consecutive Congresses in the 1820s, the average service of
Senators remained roughly constant, at approximately four years, for the next 60 years. Beginning
in the 1880s, the average began to steadily rise, predating the similar rise in the House by about
20 years. After falling dramatically for a short time in the 1910s, the average years of service in
the Senate began to steadily rise again, once again tracking the rise in average years of service
among Representatives. Average years of service peaked at 13.4 years of service in the 111th
Congress (2009-2010). At the start of the 112th Congress, the average years of service for
Senators was 11.4 years.
Analysis
Two underlying factors appear to influence variation over time in the average years of service for
members of Congresses: the decision of sitting members whether or not to seek election to the
next Congress, and the success rate of members who seek election to the next Congress.6 Each of
these components is discussed below in greater detail.
The Rate of Members Seeking Re-Election
The average years of service for Representatives and Senators is highly influenced by member
choices over whether or not to seek re-election to the chamber. If a large number of members
choose not to seek re-election, these choices will be reflected in the average years of service of
members of the following Congress, many of whom will necessarily be first-term members with
no prior service. Members might not seek re-election for any number of reasons; common
historical reasons include seeking another office, appointment to other government positions,
retirement from public service, and death.
Figure 2 plots the percentage of Representatives in each Congress who did not seek re-election to
the following Congress.7
6 In addition, short-term variation in average service is affected by the individual service tenures of members who do
not return for the following Congress. For example, because Senators Byrd and Kennedy both passed away during the
111th Congress and had Senate service of 50 and 46.2 years, the average service tenure of the 112th Congress will be
lower than if two random members of the 111th Senate did not return for the 112th Senate.
7 Senators are excluded from this analysis due to the difficulty in definitively assessing whether Senators sought re-
election prior to the enactment of the 17th amendment, which provided for the direct Senate elections.
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Figure 2. Percentage of Representatives Who Did Not Seek Re-Election
1st through 111th Congresses (1789-2011)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 2, the rate of Representatives not seeking re-election dropped dramatically
beginning in the mid-19th century. Prior to the Civil War, it was common for 40% of
Representatives or more to not seek re-election, and prior to 1887 no Congress saw fewer than
25% of Representatives not seek re-election. During the 20th and 21st centuries, the rate at which
members have not sought re-election has remained roughly constant, at an average of 11%.
Re-election Success Rate
In addition to the rate at which members seek re-election, a second important factor in
understanding variation in the average years of service in Congress is the success rate among
members who do seek re-election.8 Figure 3 plots the percentage of Representatives in each
Congress who sought re-election to the next Congress but were defeated, either in their attempt to
gain their party’s nomination or in the general election for office.9
8 Note that the two variables – member decisions to seek re-election and whether or not the member is defeated for re-
election – are not independent at the individual level; the decision to seek re-election may be based, in part, on an
estimate of the likelihood of success. Therefore, a decrease in the percentage of members who are defeated for re-
election may be indicative of greater trends, but in some cases may simply reflect an increase in members choosing not
to stand for re-election when their re-election prospects are diminished.
9 Senators are again excluded due to the difficulty in assessing Senate elections prior to the 17th amendment.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Figure 3. Percentage of Representatives Defeated for Re-Election
1st through 111th Congresses (1789-2011)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 3, the percentage of Representatives defeated for re-election has fluctuated
significantly throughout American history. As a general trend, the percentage defeated increased
during the 19th century, remained constant for the first half of the 20th century, and then decreased
during the second half of the 20th century. However, there was significant short-term variation,
which conforms to the presence of high-turnover elections throughout American history, such as
the 1872, 1890, 1894, and 1932 elections.
Discussion
The data presented in Figure 2 and Figure 3 conform with previous scholarly assessments of
congressional history, which largely conclude that during the early history of Congress, turnover
in membership was frequent and resignations were commonplace, and that during the 20th
century, congressional careers lengthened as turnover decreased and Congress became more
professionalized.
Most lawmakers in the 18th and early 19th centuries can be characterized as “citizen legislators,”
holding full-time non-political employment and serving in Congress on a part-time basis for a
short number of years. According to political scientist Randall Ripley, “In the pre-modern
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Congress, members came and went rapidly. There were few senior members. Life in Washington
was not pleasant; Congress did not seem very important.”10
According to H. Douglas Price, the lack of incentives for members to retain their seats explains
the high turnover in those early years of the House. Power was fluid in the House. The Speaker
controlled committee appointments; there was frequent change in party control, and no seniority
influence.11
After the Civil War, circumstances changed and precipitated a rise of careerism in Congress.12
Subsequently, legislative careers became professionalized, and the concept of the “citizen
legislator” became a thing of the past.13 Some observers attribute this to institutional changes in
the structure of congressional elections, such as the strengthening of the party system and the
emergence of one-party states and districts following the Civil War.14 Similarly, contemporary
scholars have identified redistricting practices as a potential factor in lengthening careers.15
Other scholars have pointed to institutional changes in congressional operations, such as the rise
of the seniority system, the development of the committee system, and new advantages of
incumbency that allowed members to generate publicity, serve constituents, and receive support
in organizing their offices and forming agendas that help them be effective legislators.16 In
addition, the development of transportation technology made travel between Washington and a
member’s home district less burdensome, potentially increasing the attractiveness of a longer
career.
10 Randall B. Ripley, Congress: Process and Policy, 4th ed. (New York: W.W. Norton and Company, 1988), p. 50. See
also H. Douglas Price, who wrote, “the distinguished Senators of the 1st Congress set the early career pattern for that
chamber: They fled the Capitol ... almost as fast as humanly possible.... Career data on the early Senate is a morass of
resignations, short-term appointees, elective replacements.... There are no notable careers in terms of service.” H.
Douglas Price, “Congress and the Evolution of Legislative ‘Professionalism,’” in Norman Ornstein, ed., Congress in
Change (New York: Praeger Publishers, 1995), p. 5.
11 Ibid., p. 16.
12 David Brady, Kara Buckley, and Douglas Rivers, “The Roots of Careerism in the House of Representatives,”
Legislative Studies Quarterly, vol. 24, no. 4, November 1999, p. 490.
13 John R. Hibbing, “The Modern Congressional Career,” The American Political Science Review, vol. 85, June 1991,
p. 404-425; Howard Baker, “‘Citizen Legislators’ Would Be Better,” Washington Post, July 8, 1983, p. 21; and Saul
Pett, “Baker Seeks to Change Face of Congress,” Los Angeles Times, August 21, 1983, pp. 2, 15.
14 Robert G. Brookshire and Dean F. Duncan, “Congressional Career Patterns and Party Systems,” Legislative Studies
Quarterly, vol. 8, no. 1, February 1983, pp. 65-78; Nelson Polsby, “The Institutionalization of the U.S. House of
Representatives,” The American Political Science Review, vol. 41, no. 1, March 1968.
15 Seth C. Mckee, “The Effects of Redistricting on Voting Behavior in Incumbent U.S. House Elections, 1992-1994,”
Political Research Quarterly, vol. 61, no. 1, March 2008, pp. 122-133; Jamie L. Carson, Erik J. Engstrom, and Jason
M. Roberts, “Redistricting, Candidate Entry, and the Politics of Nineteenth-Century U.S. House Elections,” American
Journal of Political Science, vol. 50, no. 2, April 2006, pp. 283-293.
16 On the seniority system, see Polsby, “The Institutionalization of the U.S. House Representatives”; Michael Abram
and Joseph Cooper, “The Rise of Seniority in the House of Representatives,” Polity, vol. 1, no. 1, August 1968, pp. 52-
85; on the development of the committee system, see Walter Kravitz, “Evolution of the Senate’s Committee System,”
Annals of the American Academy of Political Science, vol. 411, January 1974, pp. 27-38; George B. Galloway,
“Development of the Committee System in the House,” The American Historical Review, vol. 65, no. 1, October 1959,
pp. 17-30; on the development of member resources, see Richard Fenno, Homestyle: House Members and Their
Districts (Boston: Little, Brown, 1978); Bruce Cain, John Ferejohn, and Morris Fiorina, The Personal Vote:
Constituency Service and Electoral Independence (Cambridge, Mass: Harvard University Press, 1987).
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Finally, the emergence of national problems raised a legislative career to a new level of
importance; as the federal government took on new responsibilities, both after the Civil War and
in the early 20th century, members may have begun to view congressional office as relatively
more desirable than state office, and this may have contributed to many members’ desire to
remain in Congress.17
Patterns of Congressional Service
Distribution of Service Experience
Examining the aggregate average years of member service in a given Congress reveals little about
the underlying distribution of service among individual members. Figure 4 presents the service
experience of Representatives in the 16th, 64th, 104th, and 111th Congresses,18 divided into four
categories: first-term Representatives with no prior service in the chamber, returning
Representatives with less than four terms experience, Representatives with between four and
eight terms experience, and Representatives with more than eight terms of experience.
Figure 4. Distribution of Representative Service Tenure
16th, 64th, 104th, and 111th Congresses
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
17 Samuel Kernell, “Toward Understanding 19th Century Congressional Careers: Ambition, Competition, and
Rotation,” American Journal of Political Science, vol. 21, no. 4, November 1977, pp. 669-693; Joseph Schlesinger,
Ambition and Politics: Political Careers in the United States (Chicago: Rand McNally, 1966).
18 These Congresses were chosen for illustrative purposes, and are neither a random nor a representative sample.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 4, in all four Congresses, more than half of the Representatives have four
terms experience or less; conversely, although the proportion of members with more than eight
terms experience is greater in the more recent Congresses, such members are a small fraction of
the total number of Representatives in each Congress.
Figure 5 plots the equivalent data for the Senate.
Figure 5. Distribution of Senator Service Tenure
16th, 64th, 104th, and 111th Congresses
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 5, a high proportion of Senators have less than eight years experience in each
of the four Congresses. However, unlike the House, such Senators do not comprise a majority of
the chamber in the 104th or 111th Congress. While this may reflect the somewhat longer average
term of service for Senators (as shown in Figure 1), it may also reflect the longer constitutional
term length of Senators. Similarly, in all four Congresses presented, a higher proportion of
Senators than Representatives had served more than eight years.
Cross-Chamber Experience
A second question raised by the data is how often do members of the House or Senate go on to
serve in the other chamber? Figure 6 plots the percentage of Senators in each Congress who had
previously served in the House of Representatives.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Figure 6. Percentage of Senators With Previous Service in the House
1st through 112th Congress (1789-2013)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 6, throughout American history, a sizeable proportion of Senators have
arrived with prior service in the House, and the proportion has remained relatively constant over
time. After the initial formation of the legislature (when prior experience in one chamber was not
possible), the proportion of Senators with House experience rose to 30%, and fluctuated between
20% and 45% for the entire 19th century and most of the 20th century. It does not appear that the
change from state legislature to direct election of Senators under the 17th amendment (which
became operative over the course of the 64th, 65th, and 66th Congresses (1915-1920)) had a
significant impact on the rate of House service among Senators; there appears to be little
difference in the rate of House service among Senators in the decades prior to and subsequent to
its adoption.
In the 109th Congress (2005-2006), the proportion of Senators with House experience exceed 50%
for the first time. At the start of the 112th Congress (2011-2013), 48 of the 100 Senators (48.0%)
had previously served in the House.
A related question is how much House experience do Senators have? Figure 7 plots the average
period of House service among Senators, by Congress. The bottom line is the average amount of
House service among all Senators who began a given Congress; the top line is the average
amount of House service among Senators who previously served in the House.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Figure 7. Average Years of House Service Among Senators
1st through 112th Congress (1789-2013)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 7, among Senators with House service, the average amount of service has
typically been between five and nine years. In the 112th Congress (2009-2013), the 47 Senators
with House service had an average House service of 9.3 years, or just over four and one-half
terms.
Although rare in the contemporary Congress, throughout history members have served in the
House of Representatives after serving in the Senate. Figure 8 plots the percentage of
Representatives in each Congress who had previously served in the Senate.
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
Figure 8. Percentage of Representatives with Previous Service in the Senate
1st through 112th Congress (1789-2013)
Source: CRS analysis of ICPSR and proprietary data. Inter-university Consortium for Political and Social
Research, and Carroll McKibbin. Roster of United States Congressional Officeholders and Biographical Characteristics of
Members of the United States Congress, 1789-1996: Merged Data [computer file] 10th ICPSR ed. Ann Arbor: MI:
Inter-university for Political and Social Research [producer and distributor], 1997.
As shown in Figure 8, prior to the 1840s, it was common for a handful of Representatives to have
previously served in the Senate. Five members of the 13th and 16th Houses (1813-1815 and 1819-
1821, respectively) had formerly served in the Senate, and six Representatives in the 23rd
Congress (1833-1835) were former Senators, most notably John Quincy Adams, who had also
been President. During the 20th century, it became less common for Representatives to have
Senate experience. The last Representative to have previously served in the Senate was Claude
Pepper, who served in the Senate from 1936 until 1951, and in the House from 1963 until 1989.
Concluding Observations
Two additional observations accompany the analysis presented here. First, aggregate statistics on
member service tenures tend to disguise the variety of congressional service records found among
individual members. Some members have very short tenures of service and choose not to seek re-
election; other members have long tenures which end after re-election defeat. At the aggregate
level, average careers have become longer; in the case of any individual Representative or
Senator, however, these aggregate statistics have little or no predictive ability.
Second, the institutional and policy contexts that have shaped member decisions to seek or not
seek re-election, and succeed or fail when seeking re-election, are not static factors. Just as the
institutional contexts of elections and congressional operations have developed since the 19th
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Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2011
century, they continue to change in the contemporary Congress. To the degree that patterns of
congressional service in part reflect the incentives provided to members by these institutional
factors, it is likely that the patterns of member service tenure will also continue to change.
Similarly, the continued development of the institutional environment suggests that there is no
way to predict how the patterns of service tenure will change; just as seemingly stable 19th
century patterns rapidly changed toward the end of the century, so could the service tenure
patterns we observe today.
Author Contact Information
Matthew Eric Glassman
Amber Hope Wilhelm
Analyst on the Congress
Graphics Specialist
mglassman@crs.loc.gov, 7-3467
awilhelm@crs.loc.gov, 7-2392
Erin Hemlin
Research Associate
ehemlin@crs.loc.gov, 7-1019
Congressional Research Service
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