50-State Simulation Project

The ALARM Project


Every decade following the Census, states and municipalities must redraw districts for Congress, state houses, city councils, and more. The goal of the 50-State Simulation Project is to enable researchers, practitioners, and the general public to use cutting-edge redistricting simulation analysis to evaluate enacted congressional districts.

This repository contains code to sample districting plans for all 50 U.S. states, according to relevant legal requirements.

The sampled plans and accompanying summary statistics may be downloaded from the dataverse for this project. These consist of four files for each analysis:

• a documentation file describing data formats, analysis decisions, and data sources
• a CSV file of summary statistics for each of the generated plans
• two .rds files containing redist_map and redist_plans objects, which contain the actual shapefiles and district assignment matrices and may be used for further analysis.

Repository Structure

• analyses/ contains the code for each self-contained analysis
• R/ contains common analysis and repository management code

Data Sources

Unless otherwise noted, data for each state comes from the ALARM Project's 2020 Redistricting Data Files, which use U.S. Census demographic data (in the public domain) and election data from the Voting and Election Science Team, which is licensed under a CC BY 4.0 license.
In these cases, shapefiles are also taken from the U.S. Census Bureau.

Exceptions to these data sources are listed in the individual documentation files in the analyses/ folder.

Contributing an Analysis

Please read the contribution guidelines.