Carnegie Mellon University

Image of Wes Pegden

December 12, 2018

Mathematical Sciences Professor Appointed to State Commission on Redistricting

By Ben Panko

Jocelyn Duffy
  • Mellon College of Science
  • 412-268-9982

Associate Professor of Mathematical Sciences Wesley Pegden has been appointed by Gov. Tom Wolf to a new commission to help reform Pennsylvania's redistricting process.

The Pennsylvania Redistricting Reform Commission will "review non-partisan redistricting processes in other states that reduce gerrymandering, provide opportunities for public comment at community meetings and online, and make recommendations to the governor and legislature for a non-partisan redistricting process in Pennsylvania," according to a statement accompanying Wolf's executive order creating the body.

"This commission will bring together diverse experts and citizens to explore ways that Pennsylvania could use policies, technology and data to curb gerrymandering and ensure fair maps," Wolf said.

Pegden's work regarding fair division and redistricting has been repeatedly cited in recent debates in the United States regarding gerrymandering - the process of carving up electoral districts to disproportionately benefit one political party. A 2017 study Pegden published in the Proceedings of the National Academy of Sciences was cited in an amicus brief for a U.S. Supreme Court case regarding gerrymandering in Wisconsin. And the next year, Pegden's testimony about that same study, which used Markov chains to determine that Pennsylvania's congressional districts are almost certainly gerrymandered, helped convince the Pennsylvania Supreme Court to rule the state's congressional map unconstitutional. Pegden conducted the study with Professor of Mathematical Sciences Alan Frieze and University of Pittsburgh Assistant Professor of Computational and Systems Biology Maria Chikina.

"Our analysis of Pennsylvania's map, which is based on a general theorem we proved about detecting outliers using small random changes, demonstrated rigorously that the Congressional map of Pennsylvania exhibited more carefully crafted partisan bias than more than 99.99 percent of possible congressional districtings of the state," Pegden said earlier this year.

Beyond simply determining whether a map is gerrymandered or not, Pegden has helped develop a new redistricting protocol that could lead to fairer maps. The process would involve members of one political party in a state drawing districts to their liking, and then members of the other party being given the chance to "freeze" one district before remapping the others. Each party would continue taking turns freezing and redrawing the remaining districts until a map reflecting both parties' wishes would take form. Pegden developed the protocol with Associate Professor of Computer Science Ariel Procaccia and visiting student Dingli Yu.

"In the real world, you still might expect the results to be less than perfect," Pegden said last year. "But this would be much, much, much more fair and balanced than having one party do essentially whatever it wants."