Over at FiveThirtyEight, Nate Silver and the Monkey Cage’s own John Sides have an exchange about Nate’s evidence on the inaccuracy of Presidential election forecasts based on economic fundamentals. The exchange puts a lot of valuable points on the table. Still, I worry about what it might imply to readers outside our discipline about the prominence of Presidential election forecasting within it.
Simply put, the forecasting of Presidential elections is not among the central contemporary projects of political science. The work forecasting Presidential elections is rather like the NFL’s Pro Bowl: sure, it involves several of the discipline’s most prominent researchers, but it isn’t typically what makes those researchers prominent. And there is a reason for that. Since the first election of Franklin Roosevelt in 1932, we have observed exactly 20 Presidential elections. For statistical modelers, that is not exactly a large number. What’s more, some of the same candidates stand in multiple years, meaning that elections like 1940 or 1972 aren’t independent observations. Over this same period, we have seen pronounced changes in our political parties and in our electorate that are the subject of many books, not a single blog post. All this is to say that forecasting any one U.S. Presidential election is inherently a difficult enterprise—and one that accounts for a small fraction of the work political scientists are doing today. (This is among Jonathan Bernstein’s many reactions here, too.)
My intent is not to devalue the forecasting literature—if anything, pointing out how challenging this is should do the reverse. There is tremendous scientific value to making public forecasts, as they force researchers to commit to a specific model before outcomes are known and thus guard against models that are predictive by chance alone. The forecasting literature seems uniquely committed to this approach. But nor should the Americanist subfield of political science be judged primarily by its ability to forecast Presidential elections. Since starting graduate school, I have been to somewhere north of 400 research presentations by political scientists. Of those, the number that were on forecasting Presidential elections? Two.