Ansolabehere’s conclusion was a milestone, but it relied on something not every pollster has: money. For his research, he contracted with Catalist, a vendor that buys voter registration data from states, cleans it, and sells it to the Democratic Party and progressive groups. Using a proprietary algorithm and data from the CCES, the firm validated every self-reported claim of voting behavior by matching individual survey responses with the respondents’ voting record, their party registration, and the method by which they voted. This kind of effort is not just expensive (the Election Project, a voting information source run by a political science professor at the University of Florida, says the cost is roughly $130,000) but shrouded in mystery: third-party companies can set the terms they want, including confidentiality agreements that keep the information private.

In a response to the criticism of his paper, Richman admitted his numbers might be off. The estimate of 2.8 million non-citizen voters “is itself almost surely too high,” he wrote. “There is a 97.5% chance that the true value is lower.” 

Despite this admission, however, Richman continued to promote the claims.

In March of 2018, he was in a courtroom testifying that non-citizens are voting en masse. 

Kris Kobach, the Kansas secretary of state, was defending a law that required voters to prove their citizenship before registering to vote. Such voter ID laws are seen by many as a way to suppress legitimate votes, because many eligible voters—in this case, up to 35,000 Kansans—lack the required documents. To underscore the argument and prove that there was a genuine threat of non-citizen voting, Kobach’s team hired Richman as an expert witness. 

Paid a total of $40,663.35 for his contribution, Richman used various sources to predict the number of non-citizens registered