Partisan Gerrymandering and its Effect on Margins of Victory in the United States House of Representatives from 1968 through 2016

This paper analyzes how varying redistricting types—state legislature, advisory commissions, political appointee commissions, and independent commissions—correlate with margins of victory. The Princeton Gerrymandering Project’s statistical tests are used to classify state legislatures that have allegedly conducted partisan gerrymandering, and this study performs a pre-test post-test analysis via graphical and tabular interpretation of election data available from CQ Press’ Voting and Elections Collection. The use of GIS technology in the 2000’s combined with research to “sometimes pack but never crack” in the 2010’s and predictable voting behavior from party polarization has accelerated gerrymandering to unprecedented heights. Partisan redistricting results in landslide victories and less districts won overall for the opposing party.
Solutions to resolve gerrymandering are outlined, such as by voters lobbying state legislatures or issuing ballot initiatives, for the Supreme Court to establish gerrymandering criteria based upon statistical tests, or from changing House elections themselves, such as moving from a winner take all system to a proportional system, or having boundaries based on municipal and county boundaries as opposed to the one person one vote requirement. Independent commissions demonstrate promise in preventing gerrymandering as shown in Arizona, however a longer-term study in the future is necessary to validate its effectiveness on increasing the competitiveness of elections. Arizona has reduced margins of victories after switching redistricting authorities, however alternate “third-party” redistricting authorities—political appointee commissions and advisory commissions, are not very different than state legislatures due to political connections with these redistricting types. The purpose of this study is to examine an aspect of gerrymandering that is simple for voters to understand and decide for themselves which redistricting type is best for their state.