Job Tenure in the U Congress – 9.8 years for the House and 11.4 years for the Senate for Members of the 112th Congress, as of January 5, 2011

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 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. 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.

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.

Chosen excerpts by Job Market Monitor. Read the whole story at  “Congressional Careers: Service Tenure and Patterns of Member Service, ” by Matthew E. Glassman and Amber Hope Wilhelm.