Kosuke Imai and Ruth Greenwood wrote this column for CommonWealth on some of their data visualization projects for redistricting.

We run two projects that provide tools to help people, courts, and legislators understand how and why that is so. The Algorithm-Assisted Redistricting Methodology (ALARM) Project and the Election Law Clinic are housed in Harvard University’s Institute for Quantitative Social Science and Harvard Law School, respectively.

The Election Law Clinic partners with PlanScore to offer visualizations of the partisan biases of redistricting plans. The site includes data from 1972 to 2022 for every state, and allows users to easily see the partisan skews of congressional, state house, and state senate plans. . . . [ALARM] relies on a method developed by one of us (Professor Imai) to randomly create thousands of congressional district plans for every state with more than one district. . . .

Thankfully, the fight against gerrymandering continues in the states—and benefits from the work of PlanScore and ALARM. PlanScore’s scoring tool has been used to score over 389,000 plans in the 2020 redistricting cycle. The resulting evaluations of maps have been cited by experts, discussed by courts, introduced to redistricting commissions, and covered by journalists. These assessments have shown when proposed plans are highly skewed and should be vigorously opposed. They’ve also revealed when maps are fair and should be commended.

Likewise, one of us (Professor Imai) has used the methodology underlying ALARM as an expert in several cases, including one being argued in the Supreme Court this week. In that case, the technique supports the conclusion that South Carolina’s First Congressional District was racially gerrymandered. That district has an artificially smaller Black population than almost all randomly generated districts in the Charleston area. Outside the litigation context, activists in Ohio relied on the ALARM findings to write a constitutional amendment to end partisan gerrymandering. Signature gathering is now underway and that proposal is likely to be on the ballot in 2024.