Penn mathematics professor Philip Gressman is a part of a team of 12 mathematicians across the state that submitted a congressional district map to the Commonwealth Court of Pennsylvania to be considered for approval in the Pennsylvania redistricting process.
The map was created using computational redistricting methods, according to Gressman. This means high-performance computers were used to test different options for potential congressional maps that comply with the legal requirements.
Currently, Gressman's lawyer Sam Hirsch said that their map is one of 14 different options that are waiting for approval by the judge of the Commonwealth Court.
Redistricting occurs every 10 years based on new data collected by the U.S. Census. Gressman said that when redistricting occurs, maps are typically drawn manually. He added that this means that maps are drawn one at a time — which is a much slower process.
“If you draw maps computationally, you can crank out thousands and thousands of maps a day, with each one a little better than the last one trying to improve on the margins,” Gressman said.
Another benefit of computational redistricting is that its methodology is transparent, as the exact code they used to create the maps can be shared, Gressman said. When people hand draw maps, it is unclear why they make the decisions that they do, Gressman said.
Hirsch said computational redistricting used to be utilized to determine if hand drawn maps were gerrymandered. He added that data scientists used to generate thousands of random maps and then compare a potentially gerrymandered map to the randomly generated ones. Hirsch said if the hand-drawn map was significantly different than the randomly generated ones, it would be investigated for gerrymandering.
Gressman explained the map-making process as a “multi-objective optimization problem” since they must comply with a variety of legal standards. He said that the maps must be considered fair to both Democrats and Republicans, split as few counties as possible, and take minority representation into account — among other factors — making the process very complex and tedious.
Students on campus have also been involved with the redistricting process. Penn Democrats political director and College sophomore Lucy Kronenberg said that it is essential to highlight the major impacts that this new map could have in future years.
"[The map] determines what the districts will look like for the congressional districts in Pennsylvania for the next 10 years," Kronenberg said. "It’s especially important in a state like Pennsylvania that has been a major swing state in past years and has been so close in so many elections."
The final decision on the map is still being decided on by the judge, but the implications of this decision are major, according to Hirsch. He said that a fairly drawn map means that each voter has equal power, and, thus, will validate the value of an individual’s vote.
Gressman and Hirsch both predict that computational redistricting will become the status quo by the next redistricting cycle after the 2030 census, as their technology and efficacy are improving.
“Computers are able to solve this problem in a way that they weren’t before," Gressman said. “Computers can [draw maps] in a way that’s transparent and they can do it in a way that give the courts the opportunity to make sure that their priorities are being respected.”