The Interstate Voter Registration Crosscheck Program
A Brief History
Crosscheck's origins are innocent enough. As a part of the routine maintenance of voter rolls, states will sometimes create agreements to share their voter registration information with one another to identify registered voters who moved from one state to another. Using this data, election officials in each state would research and verify potential duplicate registrations, ultimately removing outdated registrations from the rolls.
In 2005, then Kansas Secretary of State, Ron Thornburgh, created a centrally managed data-sharing program between Kansas, Iowa, Missouri, and Nebraska. By 2011, this Crosscheck program consisted of fourteen participating states and in 2017, twenty-eight states participated in the program.
How does it work?
Each year, each participating state, sends their full voter registration file to Arkansas, which hosts a File Transfer Protocol (FTP) server to centrally store these files. Once all files are available, election officials in Kansas download all of the files to their systems. Using a program originally developed by Kansas, their IT department runs the "crosscheck".
This program analyzes the combined data from all participating states to create a file of "matches" per state. This program identifies any record where the first name, last name, and date of birth of the registered voter match between states. Even when additional data points in the file contraindicate a match, the records are included as a match. E.g., even if the person's middle name and last four digits of social security number are not the same, Crosscheck will include both "matching" records in the result file.
Once completed, Kansas sends all of the results files to the Arkansas FTP server, notifies participating states that the analysis is complete, and then states download their results files. Each state handles these results files differently, which is covered in more detail in our state-by-state analysis.