Electoral boundaries determine who votes in which races and, in many places, where voters cast in-person ballots on Election Day. Assigning each registered voter to the correct overlapping district and precinct creates a tremendously large administrative task, and large-scale data projects of this kind are vulnerable to errors. Errors of this type have been consequential in two recent close elections.
๐ What Was Examined
A method to audit the assignment of registered voters to electoral districts, with attention to both legislative districts (which determine eligibility for particular elections) and precincts (which often determine polling places).
๐งพ How the Audit Was Applied
- The described methodology was applied to Florida's voter registration file.
- The approach flags registered voters whose recorded district assignment is likely incorrect, enabling targeted verification by local officials.
๐ Key Findings
- Application to Florida's voter file identified thousands of registered voters assigned to the wrong state House district.
- Many of the flagged cases were verified and rectified by local election officials.
- Mistakes in voter-to-boundary assignment have, in at least two recent close contests, affected election outcomes.
๐ ๏ธ How Election Officials Can Use This
The technique provides a practical tool for election administrators to detect and prioritize likely misassignments for review and correction, reducing the risk that registration-file errors impact voter eligibility or polling assignments.
๐ Why It Matters
Accurate assignment of voters to districts and precincts is essential for fair, well-administered elections. A systematic auditing method helps uncover and repair errors in voter files before they can influence election results.




