Measuring Partisan Bias in Single Member District Electoral Systems

Abstract:     
In recent decades, the literature has coalesced around the dual concepts of symmetry and responsiveness, particularly the former, as the best measures of partisan bias in single-member district systems. I argue that neither accurately captures the concept of "efficiency" that is implied in most discussions of partisan advantage. I suggest a better measure of efficiency and then use this new measure to reconsider a classic study of partisan gerrymandering. Contrary to the original study findings, I show that the effects of party control on bias are small and decay rapidly, suggesting that redistricting is at best a blunt tool for promoting partisan interests.

Number of Pages in PDF File: 38

Keywords: redistricting, gerrymandering, partisan bias, electoral systems, elections, American politics

working papers series