Daily Kos Final Projection: Clinton 323ev, 88% Chance of Winning
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Over the course of this presidential campaign, Daily Kos Elections has logged 1,371 state-level presidential polls into our database. All signs point to a Hillary Clinton victory. Our forecasting model indicates that Clinton is highly likely to win key states including Colorado, Pennsylvania, New Hampshire, Virginia, and Wisconsin. In all five of these states, Clinton has never trailed in our average of the pollsand if she carries all of them, she would win the election over Donald Trump with 273 electoral votes, three more than the 270 required for victory. In addition, our model also favors Clinton in Florida, North Carolina, and Nevada. Together, those states contribute another 50 electoral votes.
That gives us our final prediction: Clinton 323 electoral votes, Trump 215.
Given that the forecast is based almost entirely on public polling data, how much can we trust the accuracy of the polls? As recently as one week ago, Clinton held such a commanding lead that our model placed her chances of winning as high as 96 percent. Since then, the race has tightened, and we currently estimate Clinton's odds of victory at 88 percent. That's enough of a change that a large and consistent polling error could make the difference for Trump. But the error would have to be very large, and very consistent. Going into Election Day, Clintons average lead in the polls is 3 points in New Hampshire, 4 points in Colorado and Pennsylvania, and 5 points in Wisconsin and Virginia.
Polling is never perfect, but systematic errors across multiple states in the same presidential election are historically not that large, or that common. Instead, the state-level errors form a distribution: In some states, one candidate outperforms the polls, and in other states, the other candidate does better. For example, in 2012, on average, the polls underestimated Obamas vote share by a small amount; nevertheless, in 22 states, his polling was higher than his eventual vote share. Polling errors are less correlated across states than you might expect.
http://www.dailykos.com/story/2016/11/7/1592391/-Daily-Kos-Elections-final-presidential-forecast-Clinton-323-electoral-votes-Trump-215