Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Political Science

First Advisor

James C. Garand


I explore the relationship between partisan votes and partisan seat allocation in U.S. state lower-house elections. Specifically, I measure the representational form (the rate of partisan seat changes given particular partisan vote changes) and partisan bias (asymmetry in the seats-votes relationship) of 441 lower-house state legislative elections in 46 states from 1968 to 1987. I then test a number of hypotheses that have been advanced to explain variation in representational form and partisan bias. Values for representational form and partisan bias are generated by creating simulations from actual election results. I simulate seat gains made by Republicans given one percent uniform party vote swings across all districts and assuming Republicans would win between 35% and 65% of the mean district vote. After generating 31 data points for each election year, I use a logit equation to operationalize representational form and partisan bias for each election year in each state. These data then become dependent variables in pooled, cross-sectional time-series analyses used to explain variation in representational form and partisan bias across time and across states. As in previous studies, I find that representational form is declining over time. I also find that representational form is a function of party competition across election districts. In elections having a large number of competitive districts, there is a rise in the value of representational form. The size of election districts (by population) as measured by Taagepera's Index has a positive but substantively weak effect on representational form. Effective district magnitude (the existence of multimember districts) also has a positive but substantively weak impact on representational form. It was thought that partisan bias would result from partisan gerrymandering during redistricting. While party control of redistricting does have the hypothesized effect in eight of the nine even-numbered election years, only in 1970, 1976, and 1982 did gerrymandering effects reach statistical significance. The results for partisan bias support recent studies that suggest that gerrymandering at the state level is not pervasive but does occasionally occur.