Back in February, when the Signal predicted that President Barack Obama will win re-election with 303 electoral votes, we wrote that "while campaigns and candidates matter, they don't matter all that much. Despite the varying quality and positions of the campaigns and candidates over the last 10 presidential elections, variables beyond their immediate control describe the outcome very well."
We won't know if our model of predicting elections is any good for another two weeks. We do know that it has held remarkably steady. The reams and reams of information about the election that have been revealed in the past eight months—for example, who the Republican candidate is—have barely shifted the political reality of the race. In fact, the only difference between February and now is that we think Virginia is now leaning in Mitt Romney's favor.
To illustrate that point, we're publishing our predictions for every day since May 1 in the form of an interactive map where you can drag the timeline back and forth.
(Our predictions actually go back to February, but they were unchanged between then and mid-May, since the model initially weighs static variables over temporal ones like polls and markets.)
Most states have drifted slowly toward their initial favorite. In early May, many states provided the whiff of promise with a 10 or even 20 percent likelihood of being picked off by the trailing candidate. This has not been a year of surprises. As you run the map from May 1 to Oct. 23, you see states fleeing to the safe, dark colors until only a handful of the true swing states remain standing.
By shifting the shading cutoff at the bottom of the map, you can see how sparse those swing states really are. If you define a swing state as one where the underdog candidate has at least a 35 percent chance of winning, only three states make the cut: Colorado and Virginia, which both lean slightly toward Romney, and New Hampshire, which is 63.9 percent likely to go to Obama. Iowa and Ohio join the fun right around that 65 percent point for Obama.
We will update this map regularly over the next two weeks. One thing we know for certain: The light colors will get sparser and sparser as we approach the day of judgment.
David Rothschild has a Ph.D. in applied economics from the Wharton School of Business at the University of Pennsylvania. Follow him on Twitter @DavMicRot.