Redistricting by Formula: An Ohio Reform Experiment

Abstract

In the last decade, Ohio reformers advocated redistricting by formula: selecting the redistricting plan that scores best on a predefined objective scoring function that combines prima facie neutral criteria with political goals of plan fairness and district competition. In the post-2010 redistricting, these reformers hosted a public competition where prizes were awarded to the best legal plan scored on the reformers’ formula. The submitted plans provide a unique opportunity to evaluate how redistricting by formula may work in practice. Our analysis finds the public yields a broader range of redistricting plans, on indicia of legal and public policy interest, than developed by the state legislature. The Pareto frontier reveals plans that perform better than the legislature’s adopted plan on one and two dimensions, as well as the reformers’ overall scoring function. Our evaluation reveals minimal trade-offs among the components of the overall competition’s scoring criteria, but we caution that the scoring formula may be sensitive to implementation choices among its components. Compared with the legislature’s plan, the reform community can get more of the four criteria they value; importantly, without sacrificing the state’s only African American opportunity congressional district.