The Geography Behind the Ballot
Building Better Election Maps in Idaho
The MIT Election Data and Science Lab helps highlight new research and interesting ideas in election science, including through research grants under our ongoing Practice-Oriented Research program.
Our post today comes from Vanessa Fry from the Idaho Policy Institute at Boise State University, based on her team's ongoing research funded by this program. The information and opinions expressed in this column represent their own research, and do not necessarily represent the opinions of the MIT Election Lab or MIT.
Most voters probably don't spend much time thinking about the geography behind their ballot. They know where they live. They register to vote. And when an election comes around, they expect to receive a ballot containing the races in which they are eligible to vote.
Behind that seemingly simple process, however, is a complicated geographic infrastructure. A voter's address must be accurately connected to congressional and legislative districts, county and municipal boundaries, school districts, and other local electoral boundaries. Those geographic layers need to be accurate, current, and accessible by the election officials responsible for administering elections.
Elections in Idaho
Idaho’s 44 county clerks are responsible for maintaining voter registration rolls. Many Idaho counties are rural and operate with limited geospatial staff or resources. In 2025, the Idaho Secretary of State’s office (IDSOS) geocoded approximately one million voter records, compared them against existing taxing district shapefiles, and flagged potential discrepancies for county review. The resulting GIS-based Shiny application quickly became a widely used administrative tool, prompting local election officials to request extensions of the analysis - particularly to school district trustee zones.
Under Idaho Code § 33-313, school districts must establish trustee zones with approximately equal populations and review those zones following each decennial census. When zones are changed, districts must submit legal descriptions, maps, and population estimates to the State Board of Education for approval, with the approved legal descriptions and maps ultimately filed with the county clerk. Yet the statute does not establish a centralized system for maintaining the underlying geographic data or require that those data be maintained in a digital format.
This project addresses that gap.
Our research team at Boise State University's Idaho Policy Institute and The Resilience Institute at Boise State, working in partnership with the Idaho Secretary of State's Office and with support from the MIT Election Data + Science Lab is examining how Idaho can build on this work to create a more reliable and sustainable system for managing election geography.
Our goals extend beyond creating a better set of maps. We are examining who should be responsible for authoritative trustee-zone data, how data should be updated and versioned over time, and how technical workflows can make geographic information more usable for election administrators. Ultimately, we want to reduce the risk of boundary-related voter registration errors while developing an approach that could be adapted to other voting districts in Idaho and beyond.
What we are learning is that the lines themselves are only part of the story.
Discovering an Existing Foundation
Following the 2010 Census, the Idaho School Boards Association (IDSBA) began helping school districts update their trustee zones to meet Idaho's redistricting requirements. Following the 2020 Census, the association again coordinated an effort to help nearly all of Idaho's school districts update their trustee-zone boundaries. That history turned out to be enormously important for our research.
We connected with IDSBA and the firm it contracted to perform the mapping work. Through that relationship, we were able to obtain nearly all of the GIS shapefiles created through the process. A shapefile is essentially a digital representation of a geographic feature - in this case, the lines and polygons that define trustee zones. Unlike a PDF or paper map, a GIS file can be combined with other geographic data and systematically analyzed.
Instead of recreating Idaho's trustee-zone geography from the ground up, we could begin assembling these existing files into a common GIS environment. And that's when the project became even more interesting.
When Lines Don't Quite Meet
As we began layering the trustee-zone files together, we found places where boundaries appear not to align perfectly. In some locations, the GIS files appear to leave small gaps between zones; in others, the digital boundaries appear to overlap.
We don't yet know whether the apparent discrepancies originate in the GIS files themselves, differences among versions of the files, or the underlying legal descriptions from which some of the maps were created. Nor should the presence of a gap or overlap in the geographic files we are examining be interpreted as evidence that a voter received an incorrect ballot. Instead, these discrepancies illustrate precisely why this work matters.
Example of apparent gaps or overlaps identified while comparing trustee-zone GIS files. The research team is examining whether these reflect differences in GIS files, legal descriptions, data versions, or other factors.
Example of apparent gaps or overlaps identified while comparing trustee-zone GIS files. The research team is examining whether these reflect differences in GIS files, legal descriptions, data versions, or other factors.
A voter's residential address has to connect accurately to the electoral districts that determine which contests appear on that person's ballot. Maintaining reliable geographic data helps election administrators make those assignments accurately and efficiently. When boundary information exists in different formats, is maintained by different organizations, or is difficult to update and share, the administrative task becomes more complicated.
The People Behind the Maps
Looking at the maps alone, however, can't tell us why these issues arise. That's why another major part of our project has involved talking with the people who work with these boundaries.
Over the summer, our team conducted interviews and conversations with county officials, school district representatives, GIS professionals, and election officials, as well as officials in other states. We wanted to understand not simply what statutes or written procedures say should happen, but what actually happens in practice.
Who creates a boundary file? Who reviews it? Where is the authoritative version stored? What happens when a district changes? How does one organization communicate that change to another? And what happens when the people responsible for these tasks have very different levels of GIS capacity?
These aren't just procedural questions. They are questions about governance and data stewardship. Creating an accurate map is only one step; someone must also be responsible for maintaining it, documenting changes, ensuring that election administrators have access to the current version, and communicating updates across organizations. By documenting these workflows, we can begin identifying where clearer responsibilities, version control, or technical processes might make the system more reliable and easier to use.
These conversations have reinforced an important lesson: election administration is not just a technical system. It is an intergovernmental and human system.
A large jurisdiction may have dedicated GIS staff. A smaller or more rural jurisdiction may rely on a consultant or on an employee for whom GIS is only one of many responsibilities. Institutional knowledge can also be dispersed across organizations and individuals. Understanding those differences is essential if we want to develop solutions that work in practice rather than only on paper.
Research with Election Administrators
Our partnership with the Idaho Secretary of State's Office has been particularly important in making that possible. This isn't research conducted at a distance from election administrators. The Secretary of State's Office has helped us identify practical questions, connect with county officials and election administrators in other states, locate data, and understand how geographic information moves through Idaho's election system.
That partnership allows us to move continually between three sources of information: what the law says, what the geographic data show, and what practitioners actually do. The places where those three don't align perfectly may ultimately tell us the most.
Where We Go From Here
Although we aren't quite ready to prescribe a solution, our emerging vision is broader than simply producing better maps. The opportunity may be to create a more consistent statewide approach for maintaining authoritative election geography, one that builds on the work Idaho has already done while making geographic information easier to validate, update, version, share, and use.
Our next steps include analyzing what we learned through our interviews, continuing to validate the trustee-zone GIS files, and examining the apparent gaps and overlaps more closely. We also plan to add address data to better understand whether, and where, these geographic discrepancies have practical implications for voter registration.
From there, we will begin testing workflows for creating, updating, validating, and sharing boundary data with the people who actually use them. The goal is to develop an approach that works not only technically, but administratively: one that recognizes differences in staffing, GIS capacity, and resources across Idaho's counties and school districts.
Our initial findings are promising. They suggest that some geographic discrepancies may be resolved by using Census block shapefiles to validate trustee zone boundaries, consistent with State Board of Education criteria directing trustee zone boundaries to follow Census block boundaries.
And while trustee zones provide our starting point, we hope the framework we develop will have applications beyond school district elections. Many of the underlying challenges (i.e., establishing authoritative boundaries, managing updates, maintaining version control, and connecting voter addresses to the correct districts) apply across election geography. A process that works for trustee zones could provide a model for improving how other voting district boundaries are managed as well.
Ultimately, the goal is not simply to make a map. It is to help develop a sustainable process that allows the people responsible for Idaho's elections to know that they are working from accurate, current, and authoritative geographic information.
For voters, that infrastructure may remain largely invisible. That's exactly how good infrastructure should work.
Author and Project Team
Author
Vanessa Fry, Idaho Policy Institute, Boise State University
Project Team
Zac Provant, Research Scholar, The Resilience Institute at Boise State
Gabe Osterhout, Data Visualization Specialist, Office of the Idaho Secretary of State
McAllister Hall, Research Associate, Idaho Policy Institute, Boise State University
Hannah Lang, Research Associate, Idaho Policy Institute, Boise State University
Trevor Yarnell, Intern, Idaho Policy Institute, Boise State University
Abigail Morgan, Intern, Idaho Policy Institute, Boise State University
