How Geospatial Mapping Can Improve Election Audits

Today’s electionline story describes 25 houses in Hamden, CT that have been incorrectly assigned to election districts since the last redistricting cycle in 2011, and have been the wrong ballots. There are charges that voters have been “disenfranchised” though it’s unclear whether the ballots were counted for the “wrong” race, or only some races were counted.

The process obviously needs to be investigated, and Secretary of State Denise Merrill is calling not just for a detailed investigation of Hamden’s procedures, but a statewide audit when it became clear that there were additional districting errors, including candidates who were elected in districts where they were not residents.

There are a lot of moving parts here and a quick scan of the various stories show an early tendency on the part of journalists to move quickly to use a partisan lens. It appears to be more an accident of unfortunate events that a Democratic registrar in Hamden has been on medical leave during the election, leaving a single person in charge, who happened to be a Republican, and the district was won by a Republican in a relatively close race (though one where the winning margin of 77 votes exceeded the number of voters who were misassigned).

While we will all need to wait to see the outcome of the audit, election scientists have been aware of this mis-mapping problem for a while because of a series of presentations that Dr. Michael McDonald and Dr. Brian Amos have given at our recent conferences.  McDonald and Amos show that mis-assignments are seldom intentional, and most often result from out of date shape files (the geo-spatial files that are used to assign geolocations to larger geographical entities, such as election precincts and districts) and mis-alignments between “street files” (the lists that jurisdictions use to match street addresses to precincts / districts) and the actual geographic boundaries of the district.

There are illustrative examples of these mis-assignments in the paper that McDonald and Amos presented at a the MIT Election Data and Sciences Lab “Election Audits Summit” in December.

I urge interested readers to follow this link to learn more about the great work being done by McDonald and Amos, and how their technology can help to improve election accuracy.