Discovery and concern
Erikson (1971) measured that U.S. House incumbents won several percentage points more than new candidates in the same district. Mayhew (1974) pointed to the rapid disappearance of marginal districts and attributed it to legislators boosting reelection through district work and publicity, raising concerns about electoral accountability.
Measurement and causes
Gelman and King (1990) offered an unbiased estimator, and Ansolabehere and colleagues (2000) used redistricting to compare newly added voters and isolate the personal vote. Lee (2008) introduced a regression discontinuity design comparing races decided by narrow margins. Cox and Katz (1996) argued that strategic entry, with strong challengers avoiding incumbents, was a key driver of the advantage's growth.
Decline and comparative research
Jacobson (2015) reported that the U.S. House incumbency advantage fell sharply after the 2000s as voting became more party-centered. Klašnja and Titiunik (2017) showed an incumbency curse in places like Brazil with weak parties and term limits, showing that incumbency effects depend on institutions and party systems.
FAQ
- What is incumbency advantage in simple terms?
- People already in office are better known and have more resources, so they do better in elections than similar challengers.
- Does incumbency advantage always exist?
- No. It has declined in the U.S. recently, and in some countries with weak parties incumbents are actually disadvantaged.
Sources reviewed: 2026-10-26
References
- Erikson, R. S. (1971). The advantage of incumbency in congressional elections. Polity, 3(3), 395–405. Early systematic measurement of incumbency advantage.
- Mayhew, D. R. (1974). Congressional elections: The case of the vanishing marginals. Polity, 6(3), 295–317. The classic 'vanishing marginals' article.
- Gelman, A., & King, G. (1990). Estimating incumbency advantage without bias. American Journal of Political Science, 34(4), 1142–1164. Unbiased estimator of incumbency advantage.
- Cox, G. W., & Katz, J. N. (1996). Why did the incumbency advantage in U.S. House elections grow? American Journal of Political Science, 40(2), 478–497. Explains growth via challenger quality.
- Ansolabehere, S., Snyder, J. M., Jr., & Stewart, C., III. (2000). Old voters, new voters, and the personal vote: Using redistricting to measure the incumbency advantage. American Journal of Political Science, 44(1), 17–34. Uses redistricting to isolate the personal vote.
- Lee, D. S. (2008). Randomized experiments from non-random selection in U.S. House elections. Journal of Econometrics, 142(2), 675–697. Regression discontinuity estimate of incumbency.
- Jacobson, G. C. (2015). It's nothing personal: The decline of the incumbency advantage in US House elections. The Journal of Politics, 77(3), 861–873. Decline amid partisan voting.
- Klašnja, M., & Titiunik, R. (2017). The incumbency curse: Weak parties, term limits, and unfulfilled accountability. American Political Science Review, 111(1), 129–148. Incumbency disadvantage in weak-party systems.