Mathematicians are deploying algorithms to stop gerrymandering

Article by Siobhan Roberts: “The maps for US congressional and state legislative races often resemble electoral bestiaries, with bizarrely shaped districts emerging from wonky hybrids of counties, precincts, and census blocks.

It’s the drawing of these maps, more than anything—more than voter suppression laws, more than voter fraud—that determines how votes translate into who gets elected. “You can take the same set of votes, with different district maps, and get very different outcomes,” says Jonathan Mattingly, a mathematician at Duke University in the purple state of North Carolina. “The question is, if the choice of maps is so important to how we interpret these votes, which map should we choose, and how should we decide if someone has done a good job in choosing that map?”

Over recent months, Mattingly and like-minded mathematicians have been busy in anticipation of a data release expected today, August 12, from the US Census Bureau. Every decade, new census data launches the decennial redistricting cycle—state legislators (or sometimes appointed commissions) draw new maps, moving district lines to account for demographic shifts.

In preparation, mathematicians are sharpening new algorithms—open-source tools, developed over recent years—that detect and counter gerrymandering, the egregious practice giving rise to those bestiaries, whereby politicians rig the maps and skew the results to favor one political party over another. Republicans have openly declared that with this redistricting cycle they intend to gerrymander a path to retaking the US House of Representatives in 2022….(More)”.