All of the nation’s leading pollsters predicted Hillary Clinton to win Michigan by massive margins. And all of them were proven wrong on Tuesday night.
In a revealing tweet, The Intercept‘s Glenn Greenwald showed the aggregate polling averages for the Michigan Democratic Primary according to RealClearPolitics. As recently as March 6, a Fox 2 Detroit poll had Hillary Clinton winning by 37 points. ARG predicted Clinton to win by 24 points in a poll conducted between March 4 and March 5:
The most consistently cited poll was Fox 2 Detroit/Mitchell, which also predicted the largest win margins for Clinton. After taking a closer look into that poll’s methodology, it’s easy to see why they got the results as wrong as they did.
On March 2, 2016, Fox 2 Detroit/Mitchell conducted a poll of likely Democratic primary voters and concluded that Hillary Clinton was leading Bernie Sanders by 28 points. The only age group they predicted would go for Sanders was the 18-29 voting bloc. But after scrolling down to the third page, it becomes clear why their results were so skewed for Clinton:
Federal law only permits us to call land lines. Because likely Primary voters are older, 54% are 60 or older and 86% are older than 50, we believe there are sufficient land line voters to get an accurate sample.
Monmouth University, another widely-respected pollster, predicted a 13-point Hillary Clinton win as recently as Monday morning. At the very bottom of the poll, Monmouth revealed their methodology for determining what makes a “likely Democratic primary voter” and how they contacted those voters:
The Monmouth University Poll was sponsored and conducted by the Monmouth University Polling Institute from March 3 to 6, 2016 with a statewide random sample of Michigan voters drawn from a list of registered voters, who participated in a primary election in 2012 or 2014 or voted in both of the last two general elections, and indicate they will vote in the presidential primary on March 8, 2016… The total sample of 704 likely voters includes 444 contacted by a live interviewer on a landline telephone and 260 contacted by a live interviewer on a cell phone, in English.
Even legendary pollster Nate Silver of FiveThirtyEight.com, who accurately predicted the 2012 election results in all 50 states with a 99 percent success rate, predicted Hillary Clinton would win the Michigan primary with 99 percent probability. At 9:25 PM Eastern Time, Silver wrote that a Sanders win would mean that pollsters everywhere need to seriously re-evaluate their calculations:
I said earlier today that I had an intuition Sanders could beat his polling in Michigan tonight, but I didn’t expect things to be quite so close. If Sanders winds up winning in Michigan, in fact, it will count as among the greatest polling errors in primary history. Clinton led by 21.3 percentage points in ourfinal Michigan polling average.
So how did the pollsters botch their Michigan predictions to such a degree? It may come down to sheer determination from young voters to show up and vote. CBS News reported that Sanders won an astonishing 82 percent of the 18-29 voter demographic. He also took home 56 percent of the vote among Michiganders aged 30 to 44. The only group Clinton won by a convincing margin was the 65 and up demographic, who voted for the former First Lady by a 2 to 1`margin.
The recent Democratic debate in Flint and Fox News Town Hall event may also have tipped undecided voters in ways that are impossible to measure. Or it’s a combination of all the above and other factors.
The moral of the story, though? Polls don’t vote — people do.