From a Classroom to the Courts: Team’s Research Cited in Gerrymandering Cases

September 20, 2019

On September 3, a unanimous state court ruling found that the legislative maps drawn up in 2017 violate the North Carolina constitution. The court ordered the maps to be redrawn.

“I’m happy that the courts listened to a mathematical, data-driven analysis of this,” said Jonathan Mattingly, a Duke University math professor, in an interview with the News & Observer. Mattingly and his Bass Connections project team conducted research investigating gerrymandering in the North Carolina legislature, which went into an expert report for Common Cause v. Lewis.

Gerrymandering in the North Carolina State Legislature (poster by Rahul Ramesh, Jacob Rubin, Haley Sink, Sam Eure, presented at Bass Connections Showcase, Duke University, April 17, 2019).

Gerrymandering has been present in our democracy since the early 19th century. Courts have struck down district maps that clearly disadvantage racial minorities, but they have often declined to intervene in cases where maps intentionally favor a political party, in part because they lack a credible way of assessing such claims.

In 2012, Mattingly watched this dynamic play out in North Carolina, where Republicans won nine of the 13 seats for the U.S. House of Representatives, even though Democrats received 51% of the votes. Interested in exploring gerrymandering, Mattingly partnered with an undergraduate on a summer research project. Using votes cast in the 2012 election to evaluate hundreds of alternative district maps, they were unable to find a single map that led to the same outcome.

Data+ summer teams in 2015 and 2018 extended the analysis to other states, and several external partners joined the effort.

Gerrymandering team at work.
Students at work on their Bass Connections project, Gerrymandering and the Extent of Democracy in America

The 2018-2019 Bass Connections team compared districting plans across states, analyzed the effectiveness of statistical tests currently used to detect gerrymandering and finished analyzing the extent of gerrymandering in the North Carolina General Assembly.

Team members also worked with four local high school students to develop two new algorithms that generate representative collections of redistricting plans and analyze how counties must be split to adhere to “one person, one vote” redistricting criteria.

Jonathan Mattingly.
Professor Jonathan Mattingly (Photo: Jared Lazarus)

The team saw this research travel all the way to the U.S. Supreme Court. Oral arguments for Common Cause v. Rucho occurred on March 26, 2019; the evidence for this case rested heavily on the expert testimony of Mattingly and the accompanying research, with significant contributions from undergraduates.

“To learn about the abstract mathematics from experts like Professor Mattingly and then go to the Supreme Court and see the Justices appreciate and cite our research was amazing,” said Luke Farrell ’19, a member of the Bass Connections team. “That moment made it clear to me that data and democracy are inextricably tied in our collective future, and that I want to work at their intersection in my own future.”

Luke Farrell and Jake Shulman at the Supreme Court.
Luke Farrell and Jake Shulman at the Supreme Court in March 2019 (Photo: Jonathan Mattingly)

“Over time we’ve developed the ability to go farther and farther [with our analysis] and we’ve also been able to bring more sunshine and more clarity to the court,” Mattingly told WUNC. “We see that often the person drawing the map has almost more of an effect on the outcome of the election than the people voting.”

In addition to Mattingly, team leaders included Greg Herschlag (Math) and Fritz Mayer (Public Policy). Joining the team of faculty and students were Andrew Chin of the UNC School of Law and the organizations Common Cause and North Carolinians for Redistricting Reform.

Bass Connections supports the Duke WILL strategic framework for shaping the university of tomorrow. The Gerrymandering project team is one example of how Duke is transforming teaching and discovery and forging partnerships across the region.

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