538 uses polling, economic and demographic data to explore likely election outcomes.
A fresh batch of close polls released Oct. 10 has Democrats worried and sent Vice President Kamala Harris’s odds of victory sliding to their lowest point yet in prediction markets for the Electoral College. Those polls — most notably from Emerson College, Marist College and The New York Times, three of the most prolific pollsters in America — show Harris and former President Donald Trump tied in the northern battlegrounds and Harris trailing heavily in Florida. But our forecast came to a different conclusion: Currently, our model gives Harris a 55 out of 100 chance of winning the majority of Electoral College votes, up from the brink of 50-50 on the evening of Oct. 9.
The difference boils down to one thing: trends, not levels. If you compare Harris’s margin over Trump in polls released Oct. 10 to the results of previous polls by the same pollsters in the same places, Harris’s margin has increased by an average of 0.4 percentage points. And according to our election model, which looks at differences in results among all pollsters to identify whether a firm leans to the left or the right, the polls from Emerson in particular have tended to underestimate Harris compared to polls with the same methodology (a mix of robocalls and online interviews) in the same geographies. This means our starting point when looking at these new polls is that Harris is doing better than they indicate, by about a point on vote margin, and that she is either holding steady or gaining ground.
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