Yogesh Uppal

Estimating Incumbency Effects in U.S. State Legislatures: A Quasi-Experimental Study

This paper estimates the incumbency effects in elections to the House of Representatives of 45 states in the United States using a quasi-experimental research method, regression discontinuity design (RDD). This design isolates the causal effect of incumbency from other contemporaneous factors, such as candidate quality, by comparing incumbents and non-incumbents in close contests. I find that incumbents in state legislative elections have a significant advantage, and this advantage serves as a strong barrier to re-entry of challengers who had previously been defeated. However, the incumbency advantage estimated using the RDD is much smaller than are the estimates using existing methods, implying a significant selection bias in the latter.