ORIGINAL PAPER Testing the Reciprocal Effects of Campaign Participation Ryan L. Claassen Published online: 5 February 2008 Ó Springer Science+Business Media, LLC 2008 Abstract Questions persist regarding the robustness of cross-sectional estimates of effects of variables that are themselves endogenous to the participation process. On one hand, the consequences of working on a campaign have interesting implications for democratic society. Less benign, however, is the possibility that failure to control for reciprocal processes leads to biased estimates of the causes of campaign par- ticipation. I use a panel of Democratic and Republican contributors interviewed following each of the past three presidential elections (1996, 2000, and 2004) to explore the relationships between campaign participation and three variables typi- cally parameterized as predictors of participation: receiving a contact, ideological extremism, and strength of party identification. The effect of strength of party identification on campaign participation proves robust; however, I find that nearly all of the associations between contacts and participation and ideological extremism and participation appear to extend from, not into, participation and past participation. Keywords Campaign participation Á Contact Á Partisanship Á Ideological polarization Á Panel data Á Structural equations Á Reciprocal causation Á Extremism Introduction While there have been numerous empirical studies of the causal determinants of voting behavior and other acts of political participation, political scientists have virtually ignored the consequences of such activity for the individual. (Finkel 1985, p. 891, emphasis in original). R. L. Claassen (&) Department of Political Science, Kent State University, P.O. Box 5190, Kent, OH 44242-0001, USA e-mail: rclaasse@kent.edu 123 Polit Behav (2008) 30:277–296 DOI 10.1007/s11109-008-9052-2