The integrity of elections is a primary concern in a democratic society. One of the most important developments in the study of elections in recent decades has been the rapid development of tools and methods for evaluation of elections, most specifically, what many call “election forensics.” I and a number of my colleagues have written extensively on election evaluation and forensics; I refer interested readers to the book that Lonna Atkeson, Thad Hall, and I wrote, Evaluating Elections, and to the book that I edited with Thad and Susan Hyde, Election Fraud.

One question that continues to arise concerns whether observed differences between election results and media exit polls is evidence of electoral manipulation or election fraud. These questions have been raised in a number of recent U.S. presidential elections, and have come up again in the recent presidential primary elections in the U.S. In a recent piece in the New York Times, Nate Cohn wrote about these claims, and why we should be cautious in the use of media exit polls to detect election fraud. Each of the points that Cohn makes is valid and important, so this is an article worth reading closely.

I’d add to Cohn’s arguments, and note that while media exit polls have clear weaknesses as the sole forensic tool for determining the integrity of an election, we have a wide variety of other tools and methods to use in situations where there are questions raised about an election.
As Lonna, Thad and I wrote in Evaluating Elections, a good post-election study of an election’s integrity should involve a variety of data sources and multiple methods: including surveys and polls, post-election audits, and forensic analysis of disaggregated election returns. Each analytic approach has it’s strengths and weaknesses (media exit polls included), so by approaching the study of election integrity using as many data sources and different methods as we can, we can best locate where we might want to launch further investigation of potential problems in an election.

I have no doubt that we will hear more about the use of exit polls to evaluate the integrity of the presidential election this fall. Keep in mind Cohn’s cautionary points about using exit polls for this purpose, and also keep in mind that there are many other ways to evaluate the integrity of an election that have been tested and used in past elections. Media exit polls aren’t a great forensic tool, as Cohn argues: the types of exit polls that the news media uses to make inferences about voting behavior are not designed to detect election fraud or manipulation. Rather, those interested in a detailed examination of an election’s integrity should instead use the full array of analytic forensic tools that have been developed and tested in the research literature.