Introduction to the declination function for gerrymanders

TL;DR

This paper explains the declination, a quantitative tool for detecting partisan gerrymanders, including its motivation, computation, and application to recent elections.

Contribution

It introduces and clarifies the declination method, providing minimal code and applying it to recent election data for the first time.

Findings

Declination effectively identifies potential gerrymanders in vote distributions.

The paper demonstrates the declination's application on recent election data.

Provides accessible code for computing the declination.

Abstract

The declination is a quantitative method for identifying possible partisan gerrymanders by analyzing vote distributions. In this expository note we explain and motivate the definition of the declination. The minimal computer code required for computing the declination is included. We end by computing its value on several recent elections.