2016 Postmortem
Related: About this forumCan Bernie Sanders Pull Off An Upset In Ohio? (538)
Demographics favor Clinton in Tuesdays Midwestern primaries, but only narrowly.
http://fivethirtyeight.com/features/can-bernie-sanders-pull-off-an-upset-in-ohio/?ex_cid=story-twitter
Bernie Sanderss win in Michigan last week was a massive upset relative to the pre-election polls of the states voters, which had shown Hillary Clinton ahead by an average of 21 percentage points. In fact, Sanders may have pulled off the biggest upset in the history of primary polling, eclipsing the previous record from 1984, when Gary Hart beat Walter Mondale in New Hampshire despite having trailed him by 17 percentage points.
When you consider Michigans demographics, however, the result wasnt all that shocking. Michigan Democrats are fairly liberal and the state has a lot of college students both factors that help Sanders. We arent just making this up as we go along; last month, we published state-by-state targets for the Clinton-Sanders race based on a few simple demographic variables in each state: specifically, its racial composition, how liberal or conservative it was, and how rural it was. Those targets had Sanders ahead of Clinton by 4 percentage points in Michigan.
Does that mean we called the upset in Michigan weeks ahead of time? No, we werent quite that good or lucky. The targets were based on a hypothetical race in which Clinton and Sanders were each winning about half the vote and half the delegates nationally. Since Clinton is ahead of Sanders nationally, she still would have been favored in our model (although not by the blowout margin that polls suggested).
Either way, the big gap between polls and demographics makes us nervous, especially because three more Midwestern states are voting today, including Ohio, where Clinton leads Sanders by about 11 percentage points in the polls. Historically, a margin like that would be quite safe: hence our polling models conclusion that Clinton is a 97 percent favorite. But after what just happened in Michigan? Id love to drop a few bucks on Sanders if a bookmaker offered 30-to-1 odds against him, as our polling model does.