Incumbency Advantage: Just Keep Winning


It’s a few weeks before the primary elections for Congress. You’re watching TV, and the anchor is talking about the upcoming Senate race in which someone is challenging the incumbent. Your mom walks into the room and watches for a second. She has not yet heard anything about the race, but once she hears that one of the individuals is a challenger to an incumbent, she immediately says, “The challenger doesn’t have a chance.” Why is your mom so sure?


You ask your mom why she thinks that. “Oh,” she says. “It’s because of the incumbency advantage.” 

The Incumbency Advantage

The incumbency advantage describes the phenomenon by which incumbents for elected office almost always win over challengers. Better fundraising apparatuses, more experience, an existing support base, easier access to resources, better name recognition, voter risk aversion, and the ability to point to a record of helping constituents all contribute to their advantage. 

How It Works

The fact that incumbents almost always win is well documented. In the 2018 Congressional elections, 91% of House incumbents and 84% of Senate incumbents won reelection. The incumbency advantage exists in presidential elections as well: seven out of the last ten presidential elections with incumbents have resulted in reelection. 

There are a number of reasons incumbents are so much more likely to win than challengers. One of the main reasons is the incumbent’s financial advantage. The amount of money raised by each campaign is an extremely accurate predictor of who will win a Congressional race: in 2018, 88.54% of House races and 82.26% of Senate races were won by the candidate who spent the most money. 

Incumbents are much better positioned to fundraise. They already have a base of supporters to reach out to for donations. They are also more likely to be supported by political action committees, or PACs, which are organizations that pool member contributions and donate to campaigns. Additionally, incumbents have experience fundraising and understand what tactics to use. The financial advantage can be seen through numbers: in the 2018 Senate races, each incumbent raised about 15.5 million dollars, while each challenger raised only about 2.1 million. Similarly, in the 2018 House races, incumbents raised approximately 1.8 million on average while challengers generally raised under 500,000 dollars. 

Additionally, incumbents have access to more resources and better name recognition. Voters who have not closely followed the race are more likely to recognize an individual who has been in office for years than a challenger who is new to the political scene. This contributes to voter risk aversion: voters might be more likely to support someone they know than take a chance on someone they don’t.

Some researchers also believe that incumbents tend to be more qualified than their challengers. A 2008 study in the American Journal of Political Science found that half of the incumbency advantage could be attributed to the higher qualifications of incumbents, although other studies have reported different results. The study also posited that the existence of an incumbent might “scare off” well-qualified potential challengers. 

Another potential contributor to the incumbency advantage is the incumbent’s ability to point to their record. This, however, can be both a blessing and a curse. On the one hand, an incumbent can point to a successful record and argue that they have already helped their constituents and will continue doing so. On the other hand, challengers can expose failures or controversies in the incumbent’s record without being as susceptible to such attacks themselves. 

So What?

The incumbency advantage can cause government bodies to be older and less diverse than the populations they represent. Since elected officials are usually reelected over and over again, it is difficult for challengers to be successful, especially those from underrepresented groups in politics. 

However, the advantage has lessened in recent years. While in the 1990s, the incumbency advantage was about eight percentage points, in the 2018 Congressional elections, it was only about three. Possibly, a growing yearning for change among voters is partly responsible. As the political scene and the nature of campaigns continue to evolve, we will see how the incumbency advantage changes too.

Think Further

  1. Do you think the incumbency advantage is a good thing, a bad thing, or neither? 
  2. Why are financial resources so important in determining who wins an election? What costs might candidates incur while running? 
  3. Why might the incumbency advantage be decreasing?


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Learn More

  1. Hirano, Shigeo, and Jr. James M. Snyder. “Using Multimember District Elections to Estimate the Sources of the Incumbency Advantage.” American Journal of Political Science, vol. 53, no. 2, 2009, pp. 292–306., doi:10.1111/j.1540-5907.2009.00371.x.
  2. “Incumbent Advantage.”,
  3. Landsman, Theodore. “Shifts in Incumbency Advantage in the US House.” FairVote, 25 Apr. 2017,
  4. Rakich, Nathaniel. “How Much Was Incumbency Worth In 2018?” FiveThirtyEight, FiveThirtyEight, 6 Dec. 2018,
  5. Weeks, Linton. “Why It’s Good To Be The Incumbent.” NPR, NPR, 11 June 2012,