Last week, Donald Trump “humbly and gratefully” accepted the Republican nomination for president, putting an end to perhaps the most unpredictable primary season in recent history.

And yet, this whole time, people still tried to predict it. Last summer at Trump’s announcement and through the fall and winter, journalists called his victory “an extreme long shot,” saying he was “not a real candidate” and had “no serious chance of winning”.

And people outside the news media seemed to agree. Betting markets run by companies like PredictIt and Betfair allow ordinary Americans to place bets on whether a certain event will occur. The more of a long shot people think the outcome is, the greater the profit would be upon its occurrence.

Betting markets, then, can be used to trace the expected probability of an event over time. In the case of Donald Trump’s nomination, it started as a serious long shot, with more than 10:1 odds, which declined over the next nine months as it became increasingly clear that Trump would be the nominee. Hillary Clinton, by contrast, had the nomination on lock this whole time, in the eyes of the market.

The profit made off of a bet for Trump and Clinton’s nomination changed over time.

These trend lines provide a look back at the events of the primary season and a glimpse into the psyches of the American people watching the unprecedented campaign unfold.

Trump’s odds of victory started out extremely volatile, falling by a third one day and doubling over the next two, as the Trump campaign’s initial provocations – calling Mexicans “rapists,” hiring actors to attend the announcement, fighting with Univision over holding the Miss USA pageant – were outside the political norm. Similar volatility occurred following his first debate appearance and subsequent conflict with moderator Megyn Kelly.

But over time, it seems, the markets started to habituate to Trump’s unique style, showing almost no reaction after Trump proposed a ban on Muslim immigration in December. At times, the movements in the markets seemed to be logical and predictable. There was a noticeable dip as Trump’s polling surge continued through the summer, and after Jeb Bush, originally an establishment favorite, left the race.

Trump said it himself when he accepted the nomination: “Who would have believed that when we started this journey” that he would receive a record-setting number of votes. Well, someone did. And now, they’re rolling in it.


Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.