# A Case for Math, Not ‘Gobbledygook,’ in Judging Partisan Voting Maps

The statistics inside recent gerrymandering cases were more complicated, yet not by much. Just as comparing registration rates between black in addition to white voters yielded a “racial gap,” comparing the voting power of Republican in addition to Democratic voters yields what the challengers inside Wisconsin case called an “efficiency gap.”

The efficiency gap can be a measure of the consequences of the two basic ways of injecting partisan politics into drawing legislative maps: packing in addition to cracking.

Packing a lot of Democrats into 1 district, for instance, wastes every Democratic vote beyond the bare majority needed to elect a Democratic candidate. Cracking Democratic voters across districts in which Republicans have smaller majorities wastes all of the Democratic votes when the Republican candidate wins.

The difference between the two parties’ wasted votes, divided by the total number of votes cast, yields an efficiency gap.

At the argument of the Wisconsin case in October, Chief Justice Roberts mocked the efficiency gap, referring to This specific by its initials, in addition to suggested which This specific was fiendishly complicated.

“The answer can be going to be because E.G. was greater than 7 percent, where E.G. can be the sigma of party X wasted votes minus the sigma of party Y wasted votes over the sigma of party X votes plus party Y votes,” he said. “in addition to the intelligent man on the street can be going to say which’s a bunch of baloney.”

Part of Chief Justice Roberts’s point was which a mathematical formula can be not a legal standard, in addition to which can be true. inside early stages of the litigation, the challengers suggested which a gap of more than 7 percent was legally significant, which does seem arbitrary.

yet the three-judge Federal District Court panel in Wisconsin which struck down a state legislative map there did not base its decision on the efficiency gap, relying instead on a more conventional legal test which considered discriminatory intent, the map’s partisan effects in addition to whether they were justified by various other reasons. The efficiency gap, the court said, was evidence which corroborated the majority’s conclusions.

The same was true inside Shelby County opinion. Chief Justice Roberts did not contend which a particular racial gap proved a constitutional violation, yet only which his numbers were Great evidence of powerful adjustments. (This specific was probably just as well, as a recent ProPublica article suggested which there were flaws inside chief justice’s methodology.)

The Supreme Court has not hesitated to use social science to explore disparities between two groups. In 1954, in Brown v. Board of Education, for instance, the court cited studies via psychologists in addition to others to show the negative effects of segregation in public schools.

On Friday, North Carolina lawmakers asked the Supreme Court to put Judge Wynn’s ruling on hold while the court considers two pending cases. In addition to the Wisconsin case, Gill v. Whitford, No. 16-1161, the court has also taken up one via Maryland, Benisek v. Lamone, No. 17-333.

One way or another, the Supreme Court can be very likely to issue a landmark decision on political gerrymandering by June. Judge Wynn’s 190-page opinion surveyed many topics, yet its most striking passages seemed addressed to justices who had majored inside humanities.

“The Constitution does not require the federal courts to act like Galileo’s Inquisition in addition to enjoin consideration of brand new academic theories,” Judge Wynn wrote.

“which can be not what the founding generation did when This specific adopted a Constitution grounded inside then-untested political theories of Locke, Montesquieu in addition to Rousseau,” he wrote. “which can be not what the Supreme Court did when This specific recognized which advances in our understanding of psychology had proven which separate could not be equal.”