Conformity Effects and Geographic Polarization: Evidence from an Event-Study Analysis of Residential Mobility in the U.S.

Abstract

We propose that individuals are more politically active in more like-minded social environments. To test this hypothesis, we combine administrative data from the Federal Election Commission and the United States Postal Service. We identify 45,000 individuals who contributed to Barack Obama’s 2008 presidential campaign and who changed residences either before or after the 2012 election cycle. We examine whether living in an area with a higher share of Democrats causes higher contributions to Obama. We disentangle the direction of causality by exploiting the timing of residential mobility with an event-study analysis. We find that conformity effects are economically significant: increasing the share of Democrats by 1% increases the contribution to Obama by 0.11% (p-value