Wednesday, September 30, 2015

"The ‘Hot Hand’ Debate Gets Flipped on Its Head"

From the Wall Street Journal:
A new paper shows how a simple coin toss may prove that basketball players really can get hot
People have been hunting for proof of the hot hand in basketball longer than Stephen Curry has been alive.  
The search has lasted three decades and exhausted almost all options. But the results were usually the same. There was no evidence of the hot hand. A player who made a shot was no more likely to make his next shot. 
Then something strange happened this summer. Economists, psychologists and statisticians started talking about a new paper on basketball. It claimed that the hot hand really does exist. But what made it truly mind-boggling was that the authors used the simplest scientific method: coin flips. 
The new paper, written by Joshua Miller and Adam Sanjurjo, begins with a riddle. Toss a coin four times. Write down what happened. Repeat that process one million times. What percentage of the flips after heads also came up heads? 
The obvious answer is 50%. That answer is also wrong. The real answer is 40%—and the authors say their correction should alter years of thinking about the hot hand. 
The fallacy of the hot hand was established in a classic 1985 study that has since become a part of the social-sciences canon. The paper’s conclusion—that the appearance of shooting streaks was a misreading of randomness—was so counterintuitive that many refused to believe it. The uproar hasn’t abated over the years, yet even the most promising follow-ups found only a tepid hand. The feeling that you can’t miss after making several shots in a row was still a “massive and widespread cognitive illusion,” as the Nobel Prize winner Daniel Kahneman has written.
Nobel laureates think about the hot hand because it’s a bias that shapes important decisions. For these academics, the hot hand isn’t an isolated basketball occurrence. It’s an accessible example of how human beings behave with consequences for almost every industry. 
Now, though, comes the most intriguing argument that human intuition wasn’t wrong. A basketball player who shoots the same percentage after a streak of makes as he does after a streak of misses was long accepted as proof against the hot hand. Miller and Sanjurjo’s paper asserts it’s actually evidence of the opposite....MORE

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