People Can Predict Elections (Even When Polls Can’t)

New research from David Rothschild and Justin Wolfers:

Most pollsters base their election projections off questions of voter intentions, which ask “If the election were held today, who would you vote for?” By contrast, we probe the value of questions probing voters’ expectations, which typically ask: “Regardless of who you plan to vote for, who do you think will win the upcoming election?” We demonstrate that polls of voter expectations consistently yield more accurate forecasts than polls of voter intentions. A small-scale structural model reveals that this is because we are polling from a broader information set, and voters respond as if they had polled twenty of their friends. This model also provides a rational interpretation for why respondents’ forecasts are correlated with their expectations. We also show that we can use expectations polls to extract accurate election forecasts even from extremely skewed samples.

In an Oct. 26-28 YouGov poll, 45% said Obama would probably or definitely win, 18% said Obama and Romney were equally likely to win, and 29% said Romney would win (8% did not know).  In Gallup’s most recent poll, Obama’s advantage is 54%-34% (11% did not know).  Gallup notes that its own question accurately predicted the winner of the popular vote in the 1996-2008 presidential elections.  Wolfers is working on an estimate from 2012, which I’ll report here when it’s ready.

[Cross-posted at The Monkey Cage]

John Sides

John Sides is an associate professor of political science at George Washington University.