The Princeton Gerrymandering Project conducts nonpartisan analysis to understand and eliminate partisan gerrymandering, state by state.

The Supreme Court acknowledged the validity of our math in 2019 but declined to act. Looking ahead, the strongest route to reform is at a state-by-state level — a federalist approach.

Our interdisciplinary team aims to give activists and legislators the tools they need to detect offenses and draft bulletproof, bipartisan reform. Our analysis has been published widely, and our work is used by reformers, regardless of partisan affiliation, to improve community representation.

We translate math into law, and law into math.

Election laws and the Constitution are silent on critical issues of representation and districting. By understanding the real-world impacts of the law as it stands, we can help patch holes and fix bugs. Despite a recalcitrant Supreme Court, paths to reform remain open through state courts, ballot initiatives, and legislation, and in the long term, national legislation. In the article “Laboratories of Democracy”, we describe an interdisciplinary approach where mapmaking, statistics, and law can work together to fill a current legal void.

We have developed a Redistricting Report Card that converts metrics of partisan and racial performance data to a grade, using quantitative rubrics that are the same from state to state. These metrics use our own statistical analysis standards, computational simulations, and data from the U.S. Census, the Voting and Election Science Team (VEST), and the Redistricting Data Hub. We gratefully acknowledge the efforts of the Redistricting Data Hub and VEST in gathering precinct-level election data from across the nation.

We provide rigorous standards to constrain bad acts.

We develop and use mathematical tests that rigorously diagnose unequal opportunity and unfair outcomes in district maps. For instance, the three statistical tests for gerrymandering described in the Stanford Law Review are summarized on the tests page. They are applicable in claims against individual districts and in claims against statewide districting schemes. These claims can be brought in state courts under different legal provisions.

We help scholars, advocates, and lawmakers.

The Gerrymandering Project supports state- and federal-level reform efforts to eliminate partisan gerrymandering. We identify opportunities and loopholes in existing law that shape how district maps are drawn. We can help analyze and craft reform language to help advocates translate their own ideals into practical solutions. We have produced nonpartisan projects and reports for reformers in Virginia, Michigan, and Ohio, with the goal of advancing redistricting reform in those states. In December 2018, we drew attention to weaknesses in a redistricting reform bill proposed by New Jersey lawmakers and testified about our findings in committee hearings. In 2021, Prof. Sam Wang, assisted by Princeton Gerrymandering Project staff, served as the nonpartisan technical expert on New Jersey’s congressional and legislative redistricting commissions. In 2023, the Electoral Innovation Lab, a project that began at the Gerrymandering Project, became an independent 501(c)(3) organization.

Projects

State Reports

We prepare reports that include demonstration maps, as well as statistical and legal analyses to help good-government groups craft lasting reform strategies.

A Citizen’s Guide to Redistricting in Ohio

A Commissioner’s Guide to Redistricting in Michigan

Citizen’s Guide to Redistricting in Virginia

A Judge’s Guide to Redistricting

Code, Data, and Repositories

For its simulations, the Gerrymandering Project uses precinct-level geographic data from across the country. Major nationwide efforts have made redistricting data widely available for public use, including the Redistricting Data Hub, the Voting and Election Science Team, and Dave’s Redistricting App.