Traveling talk on gerrymandering merges mathematics, politics

Since Steve Dunbar, professor emeritus of the Department of Mathematics at the University of Nebraska–Lincoln, and Kristie Pfabe, professor and department chair of mathematics at Nebraska Wesleyan University, discovered their shared interest in the subject of gerrymandering, they have given a talk to 22 different groups since 2018.

For two years, Steve Dunbar and Kristie Pfabe have been collaborating on a traveling talk about the timely subject of gerrymandering and the ways in which mathematics can be used to address this societal issue and help to eradicate it.

Since Dunbar, professor emeritus of the Department of Mathematics at the University of Nebraska–Lincoln, and Pfabe, professor and department chair of mathematics at Nebraska Wesleyan University, discovered their shared interest in the subject, they have given the talk to 22 different groups, ranging from a 15-minute presentation to a four-week mini-course for adults.

"My hope for the talk is that people will understand what gerrymandering is so that they can speak of it in simple terms to family, friends, and neighbors, and that people will understand that with mathematics and computer science, it is possible both to measure the extent of gerrymandering and to make the redistricting process far more objective," Pfabe said.

Nationwide, there is currently a much greater awareness of the abuses and misuses of the redistricting process, Dunbar said.

"This is partly due to some high-profile gerrymandering court cases in Pennsylvania, North Carolina, and Maryland, and partly due to the fact that mathematicians, data scientists, political scientists, citizens, and advocacy groups have some new tools to uncover gerrymandering practices. As a result of both trends, in 2018 and 2020, Colorado, Michigan, Missouri, and Virginia have passed laws and constitutional amendments to put redistricting in the hands of non-partisan redistricting commissions, joining Arizona and California," Dunbar said.

Dunbar cited his interest in the intersection of mathematics and politics—probability theory (specifically the Markov Chain Monte Carlo method) and learning about graph theory and working with large data—as his inroad to the subject of gerrymandering.

"I've always had an interest in the applications of mathematics to biology, economics, and political science," Dunbar said, "so I was intrigued by mathematicians getting involved in a political issue and bringing some mathematical tools and viewpoints to the redistricting process."

Pfabe's interest in gerrymandering comes from her broader concern about voter suppression. She wrote an article for the Lincoln Journal Star against a voter ID bill and twice testified before the Nebraska Unicameral's Committee on Government, Military and Veterans' Affairs on such legislation.

She feels mathematicians play an important role in explaining and informing local and national issues. She has written social media posts to explain why giving voter information to the Election Integrity Commission would have been dangerous; to show how taxation of food disproportionately affects families on the lower end of the economic scale; to share the mathematics behind 'pooled COVID testing'; and to share why the case fatality rate is not a good measure to say how well a country is doing in fighting the virus.

Besides speaking to groups such as the Kiwanis Club, Rotary Club, UNL's STEM CONNECT Scholars group, and the League of Women Voters (their first talk), Dunbar and Pfabe added hands-on activities when speaking to the Lincoln Area Math Teachers' Circle and the Osher Lifelong Learning Institute.

"We used games and exercises to illustrate some of the ideas, like gerrymandering a mythical State of Squaretopia. We also used pipe-cleaners to illustrate the idea that a circle encloses the greatest area with a fixed perimeter," Dunbar said.

Frequent Math Teachers' Circle presenters, Dunbar and Pfabe have a working relationship that goes back to their days at UNL when Pfabe was a graduate student and Dunbar was faculty.

The journey to their gerrymandering talk partnership began for Pfabe with a pivotal moment in which she attended the Metric Geometry and Gerrymandering Group conference on Geometry of Redistricting in the fall of 2017. This first conference, held in Boston, Massachusetts, stemmed from a working group under the leadership of faculty at Tufts University and the Massachusetts Institute of Technology and set off a series of regional conferences, one of which Dunbar attended at the University of Wisconsin-Madison later in 2017.

Following his attendance of the conference in Wisconsin, Dunbar gave a solo talk on gerrymandering to UNL's discrete mathematics seminar. A Wesleyan colleague, who received announcements of these seminars, mentioned to Pfabe that Dunbar had attended a conference on gerrymandering. Pfabe subsequently reached out to Dunbar to ask for some advice on her upcoming solo talk to the Nebraska section meeting of the American Mathematical Association for Two-Year Colleges. And so began their collaboration.

"It's been a really neat experience for me to work with one of my professors from graduate school," Pfabe said. "Steve and I have different strengths, and I feel that we have used these strengths to improve our presentations; the first talk we gave is pretty different from the last one."

Besides the fun factor, Dunbar also appreciates the chance to present complementary viewpoints.

"This talk raises awareness of not only the abuses of gerrymandering and how it biases the political environment and robs votes, but it also shows that mathematicians have a lot to contribute to modern social and political issues," Dunbar said. "It shows people that mathematics can be fun, useful, interesting, and different from what is encountered in school."

Dunbar and Pfabe both feel mathematicians can use their skills and knowledge to actively engage in what they refer to as "civic math."

"It is important to me to use my skills this way and to communicate the mathematics of civic life in simple terms," Pfabe said.

– Stephanie Vendetti