Polling prognosticators jettison tools from 2016

Pioneer in field Silver preaches great caution

NEW YORK — The one thing most likely to conjure nightmares of the 2016 election night for opponents of President Donald Trump is the Needle.

A graphic on The New York Times’ website, the Needle measured in real time the probability of victory for Trump or Hillary Clinton as votes were counted. Its steady movement triggered anxiety for Clinton supporters, who repeatedly refreshed the page, and elation for Trump fans.

The Needle won’t make a reappearance on Nov. 3, one change in the world of election probability gurus following the unexpected 2016 result.

Nate Silver’s influential FiveThirtyEight blog used a number, not a needle, for the same task four years ago but won’t on election night 2020.

Silver said the change had more to do with uncertainties created by the high volume of early voting this year than with any failures in 2016.

“I just think people need to be exceptionally careful,” he said.

Silver has been a pioneer in the specialized field of statistic experts who crunch the growing number of public opinion polls to put them in a broader context. Nate Cohn of the Times, with his blog The Upshot, is also a leader.

They amplified the shock of 2016 by predicting a high probability of a Clinton victory. Samuel Wang of the Princeton Election Consortium said she had a 93 percent chance of victory, a call that later led him to eat a cricket live on CNN as penance.

Cohn went into election night saying Clinton had an 85 percent chance of winning, and that served as the Needle’s baseline. The graphic was a meter, shaped like a half-clock, with outcomes that ranged from a “very likely” Clinton win to the same for Trump.

At 8:02 p.m. Eastern time on election night, the Needle pointed sharply to the left and a “likely” Clinton win. It moved to the right as results came in. By 10 p.m., the pointer headed into the “toss-up” category, and less than two hours later, it was “leaning Trump.”

You know how the story ended. Silver was more cautious heading into election night; his final forecast gave Clinton a 71 percent chance of winning and Trump a 29 percent likelihood. For that, he was criticized by those who couldn’t conceive of a Trump win.

While a 29 percent chance may not seem like much, Silver notes that a .290 batting average is pretty decent for a major league baseball player. That’s where the probability experts acknowledge their weakness, in communicating that a Trump victory was not impossible.

Cohn later wrote: “We failed at explaining that an 85 percent chance is not 100 percent.”

Nam Y. Huh The Associated Press file Nate Silver, creator of the FiveThirtyEight blog, said analysts of real-time win probability “need to be exceptionally careful” in their calls in the election this year.