Quarterly Journal of Political Science > Vol 15 > Issue 4

The Direct Primary and the Incumbency Advantage in the US House of Representatives

Michael P. Olson, Department of Political Science, Washington University in St. Louis, USA, michael.p.olson@wustl.edu
Suggested Citation
Michael P. Olson (2020), "The Direct Primary and the Incumbency Advantage in the US House of Representatives", Quarterly Journal of Political Science: Vol. 15: No. 4, pp 483-506. http://dx.doi.org/10.1561/100.00018168

Publication Date: 08 Oct 2020
© 2020 M. P. Olson
Elections,  Electoral behavior,  Electoral institutions
Incumbency advantagedirect primarylegislative elections


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In this article:
The Direct Primary and the Incumbency Advantage 
Data and Empirical Strategy 


What is the relationship between the United States' uniquely democratic nominating procedure — the direct primary — and the incumbency advantage? I argue that the adoption of primary elections incentivizes legislators to cultivate and voters to use non-party reputations, leading to an increase in the incumbency advantage. To test this argument, I combine a regression discontinuity approach for estimating the incumbency advantage with a panel design to identify effects of direct primary adoption. The estimates from this differences-in-discontinuities design suggest that the adoption of the direct primary increased the incumbency advantage by about two percentage points. These results offer one possible institutional basis for the incumbency advantage in the US House of Representatives and provide new evidence for the central importance of primary elections in American politics.