Graduation Year


Date of Submission


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Cameron Shelton

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© 2016 George J Vojta


This paper measures the party incumbency advantage for the Democratic Party in state legislatures nationwide. To do so, this paper employs regression discontinuity design (RDD), following the structure laid out in Lee (2008). The results show a stronger incumbency advantage in state legislatures than the 8% figure found for U.S. House of Representative elections by Lee (2008), with a finding of a 14% advantage for lower houses nationwide and a 12% advantage for upper houses nationwide. Furthermore, this paper finds a strengthened incumbency advantage in states that hold their elections in off-years (34% in lower houses and 21% in upper houses). The paper concludes by suggesting that the boosted incumbency advantage for off-year states is a consequence of depressed voter turnout, testing this hypothesis using the Virginian lower house as a case study. Analysis suggests that the incumbency advantage drops substantially to 8% during years with a gubernatorial race and high voter turnout, and jumps substantially to 25% during years without a gubernatorial race and low voter turnout. However, large errors prevent these results from being statistically significant.