The Weighted Districts Method of Evaluating Partisan Gerrymandering : Weighting Districts by Vote Share

This article presents the Weighted Districts Method (WDM), a gerrymandering measure that quantizes the actions of a gerrymander by weighting the value of each district in a redistricting plan. By plotting all district weights on a dot plot, the user can actually 'see' a gerrymander. The average of a plan’s district weights gives the WDM result.This past decade has brought an unprecedented flood of gerrymandering inquiry. Amid the barrage of articles and court cases in the past few years, the Efficiency Gap has become the most cited gerrymandering measure. A 2017 summary (A Formula Goes to Court, Bernstein and Duchin) proposes that the Supreme Court accept the Efficiency Gap as a first draft of a gerrymandering standard while conceding it has five “grave limitations.” Though not its original intent, the WDM ‘fixes’ these five limitations, including the discontinuity (gap) in the Efficiency Gap weighting function. In doing so, the WDM is shown to be the superior measure.The WDM produces stable, accurate results that, when plotted via the dot-plot, visually display a gerrymander in a way the public and our courts can easily understand. A partisan gerrymander manipulates district boundaries to maximize the number of legislative seats for one party. It does this by creating a small number of packed districts for the losing party and a majority of ~60% districts for the winning party. By weighting the value of these exact behaviors, the WDM provides a precise measure of gerrymandering