Strategic Interaction and Candidate Competition in U.S. House Elections: Empirical Applications of Probit and Strategic Probit Models

In recent work, Signorino (American Political Science Review 93:279–297, 1999; International Interactions 28:93–115, 2002) has sought to test statistical models derived from extensive-form games in the context of international relations research focusing on conflict and interstate bargaining. When two or more actors interact with one another under conditions of uncertainty, Signorino demonstrates that it is necessary to incorporate such strategic interaction into the underlying model to avoid potential threats to statistical inference. Outside the realm of international relations research, however, there have been limited applications of Signorino's strategic probit model in understanding strategic interaction. In this article, I present an empirical comparison of probit and strategic probit models in the context of candidate competition in House elections during the 1990s. I show that incumbent spending deters challenger entry and factors such as minority party affiliation and redistricting significantly affect incumbent career decisions, findings that run counter to those reported in the nonstrategic model. Overall, the results illustrate that failing to account for strategic interaction can lead to biased and inaccurate estimates related to challenger and incumbent entry decisions.