Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2017

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; the 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 115th Congress, as of January 3, 2017, when the Congress convened, was 9.4 years for the House and 10.1 years for the Senate. The average years of service for Members of the 114th Congress, as of January 6, 2015, when the Congress convened, was 8.8 years for the House and 9.7 years for the Senate. The average years of service for Members of the 113th Congress, as of January 3, 2013, when the Congress convened, was 9.1 years for the House and 10.2 years for the Senate.

Two underlying factors appear to influence variation over time in the average years of service for Members of Congress: 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 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-114th Congresses, by Jennifer E. Manning and R. Eric Petersen

This report will be updated at the beginning of each Congress.

Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2017

January 3, 2017 (R41545)
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Contents

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; the 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 115th Congress, as of January 3, 2017, when the Congress convened, was 9.4 years for the House and 10.1 years for the Senate. The average years of service for Members of the 114th Congress, as of January 6, 2015, when the Congress convened, was 8.8 years for the House and 9.7 years for the Senate. The average years of service for Members of the 113th Congress, as of January 3, 2013, when the Congress convened, was 9.1 years for the House and 10.2 years for the Senate.

Two underlying factors appear to influence variation over time in the average years of service for Members of Congress: 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 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-114th Congresses, by [author name scrubbed] and [author name scrubbed]

This report will be updated at the beginning of each Congress.


Congressional Careers: Service Tenure and Patterns of Member Service, 1789-2017

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; the 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 114th Congresses were compiled from the Congressional Directory.2 Data for new Members of the 115th Congress 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 48,872 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 Conyers, Jr. is the longest serving Representative, with 52 years of service at the beginning of the 115th Congress (2017-2019). As of the beginning of the 115th Congress, Representative Conyers also has the most cumulative congressional service. The longest serving Senator is Patrick Leahy, with 42 years of service in the Senate at the beginning of the 115th Congress.

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 115th Congress.

Figure 1. Average Service Tenure, Senators and Representatives

1st through 115th Congress (1789-2019)

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; the 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. The 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 2009-2010). At the start of the 115th Congress, the average years of service for Representatives was 9.4 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 nation, 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 rise steadily again, once again tracking the rise in average years of service among Representatives. The average years of service peaked at 13.4 years of service in the 111th Congress (2009-2010). At the start of the 115th Congress, the average years of service for Senators was 10.1 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

Figure 2. Percentage of Representatives Who Did Not Seek Re-Election

1st through 114th Congresses (1789-2017)

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

Figure 3. Percentage of Representatives Defeated for Re-Election

1st through 114th Congresses (1789-2017)

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 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.

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. Table 4 presents the service experience of Representatives in the 16th, 64th, 104th, and 115th Congresses,18 divided into four categories: first-term Representatives with no prior service in the chamber, returning Representatives with less than four terms of experience, Representatives with between four and eight terms of experience, and Representatives with more than eight terms of experience.

Figure 4. Distribution of Representative Service Tenure

16th, 64th, 104th, and 115th 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 Table 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 fraction of the total number of Representatives in each Congress.

Table 5 plots the equivalent data for the Senate.

Figure 5. Distribution of Senator Service Tenure

16th, 64th, 104th, and 115th 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], 199)7.

As shown in Table 5, a high proportion of Senators have less than eight years' experience in each of the four Congresses. However, compared with Representatives, such Senators do not make up as large a proportion of the chamber; in each Congress, an equal or higher proportion of Senators than Representatives had served more than eight years. 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.

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.

Figure 6. Percentage of Senators with Previous Service in the House

1st through 115th Congress (1789-2019)

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 within a fairly constant range 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 exceeded 50% for the first time. At the start of the 115th Congress (2017-2019), 50 of the 100 Senators (50%) 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.

Figure 7. Average Years of House Service Among Senators

1st through 115th Congress (1789-2019)

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 115th Congress (2017-2019), the 50 Senators with House service had an average House service of 9.2 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.

Figure 8. Percentage of Representatives with Previous Service in the Senate

1st through 115th Congress (1789-2019)

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 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, Analyst on the Congress ([email address scrubbed], [phone number scrubbed])
[author name scrubbed], Graphics Specialist ([email address scrubbed], [phone number scrubbed])

Footnotes

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, 113th Congress, S. Pub 113-12, 112th Cong., 1st sess. (Washington: GPO, 2013); U.S. Congress, Joint Committee on Printing, Official Congressional Directory, 112th Congress, S. Pub 112-12, 112th Cong., 1st sess. (Washington: GPO, 2011); 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, 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.

CQ Roll Call, Guide to the New Congress, 115th Congress, November 9, 2016.

4.

Each case represents a Member-Congress. For example, a Member who served for eight 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.

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 begun his 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 had more than 20 years of prior service), it is a practical analytical constraint only for the first five or seven 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 fifth and eighth Congresses and in the seventh and ninth Senates, which indicates that while the artificial constraint may be theoretically suppressing the aggregate service average, it is no longer a dominant practical factor.

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 is lower than if two random members of the 111th Senate had not returned 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.

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.

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) pp. 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, MA: Harvard University Press, 1987).

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.