Nov 8, 2017

Researchers propose a gaming solution to gerrymandering

Illustration: Rebecca Zisser / Axios

The political world is waiting for the Supreme Court ruling on gerrymandering — the practice in which the party in power artfully redraws voting districts so its members can more easily win election. One problem, though, is that, even if the justices create a definition for gerrymandering, experts must then get to work producing a broadly accepted prescription for it. But researchers at Carnegie Mellon University suggest that a gaming solution may work.

Why it matters: The CMU researchers say their system outperforms using an independent body to draw districts — the leading solution many propose at the moment — because independence can be subjective.

In a new paper, Wesley Pegden, Ariel Procaccia and Dingli Yu plot out a game of alternating rounds of play, in which each political party takes its best shot at maximizing advantage on a districting map.

Player A maps a state into districts; Player B then peruses those districts, and selects one to freeze — no changes can now be made to that district. Then Player B takes over, mixes up the game board as he or she sees fit, and now Player A freezes another district in place, and so on, until all the districts in the state are fixed. In the end, neither player has an inordinate chance to pack districts with an unequal voting balance.

  • "In the real world, you still might expect the results to be less than perfect," says Pegden. "But this would be much, much, much more fair and balanced than having one party do essentially whatever it wants."
  • There is more work to do, he says — their proposed system cannot simply be installed in Wisconsin, for instance, the venue of the dispute in the Supreme Court case. "The point is that it shows that a major obstacle to fair districtings (where do you find independent agents?) can be overcome by using a fair division approach to drawing the districts," Pegden says.

Using mathematical reasoning, the researchers found that players did not necessarily take the simple choice of freezing a district in which they have a majority. For example, Player A might concede a large majority in a district to Player B, with the goal of reducing the number of supporters available to "B" later in the game.

"After freezing that district, there are much fewer supporters of B left, and that could allow A to win more districts down the road," Procaccia told Axios in an email exchange. "An optimal strategy looks into the future and considers all possible outcomes."

Go deeper for gaming wonks: "Districts can be good for Player A either because Player A wins a district without using too many more than 50% of the votes to do so, or because Player B wins but needs to waste a lot of votes to do so," says Pegden.

Go deeper