Tuesday, November 15, 2016

Trump -- Horseplayers Shouldn't Have Been Surprised

Donald Trump's Electoral College victory last week shocked, shocked the mainstream media punditocracy and, apparently, both campaign staffs and the candidates themselves. After all, Clinton had maintained a steady lead in the opinion polls ever since the summer party conventions, and the received wisdom was that any other result was inconceivable.

So when Trump actually won, the first reaction, at least in my deep-blue part of the world, was incomprehension. How could the polls have been "wrong"?

But, in fact, the polls weren't wrong. If one followed fivethirtyeight.com, the premier poll-aggregation site, one saw that the election was, in fact, looking more and more like a horse race. And, whatever the odds, they are no guarantee. As some say, that's why they run the race.

When I began to be one of those who compulsively checked fivethirtyeight a dozen times a day, it was reporting that Clinton had about an 80% chance of winning the election. In horseplayer terms, that made her a 1-4 favorite. Pretty safe, but, as we all know, heavy favorites do on occasion lose. Still, not too much cause for alarm; most of us would be willing to single a 1-4 shot in our Pick Six or Pick Four bets.

[An aside re the odds: the election odds derived from the fivethirtyeight percentages are "true odds," based on 100% of the probability of the event. If Clinton was 1-4 (80%), then Trump was 4-1 (20%). That's different from the situation in horse racing. In New York, the takeout on a win bet is 16%, so the total probability reflected by the odds is 120%, not 100%. In a race, a 1-4 horse would have a crowd-determined probability of only 67%, and the 4-1 shot would have a 16.7% chance. But you all knew that already.]

As the election got closer, Clinton, while still an odds-on favorite, began to look more vulnerable. Her implied odds slipped, from 1-4 to 2-7, then to 1-3, 2-5. 1-2 and, on the eve of the election, to 5-9, implying only a 64% chance. If you ran the election a thousand times, yes, Clinton would win most of them. But, for better or worse, we run the Presidential election only once each cycle, and the 9-5 shot is going to win an appreciable percentage of the time.

So, distaste, fear and loathing, fine. But not shock. It could happen, and it did. Let's move on to the next race

Why is this so hard for the media and the party insiders to understand? There seems to be something about statistics and probability that baffles otherwise perfectly intelligent people. That difficulty served me well when I was a high school bookie, setting a line that added up to 150% and that wasn't questioned by my gullible classmates. But pillars of the media, even if self-designated, should know better.

The new Common Core standards that are being adopted by American schools include what looks to me like a pretty sensible unit on statistics and probability. Perhaps, with time, probability literacy will become more common. But we have a long way to go when even the elites don't understand.

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