The NBA playoffs are heating up (and The Heat are at 1 to freakin’ 3 which, in my book, is an awful bet but what do I know?) and sports fans everywhere start hearing about the “hot hands” phenomenon. Who’s “hot?” What player can carry his team to the championship? Who’s playing way above the norm at this critical time of the year?
This topic actually pops up everywhere. Hockey goalies seem unbeatable – they just know where the puck is heading and stop anything thrown at them. Quarterbacks are on fire – pass after pass finds down-field receivers clean in stride. But it’s in basketball that the effect is most prominent. It’s tough to miss those moments where a player can seemingly do no wrong. He’s in a state of grace, on fire, cannot miss. He’s draining 22 footers like they were layups, nailing ‘em from the corners, all net from the top of the key.
Are these moments real? That is, real in the sense that when they occur they are mathematically or metaphysically special? I’m not trying to split hairs; this is a serious question. When an all-pro quarterback seems to be in that ‘zone’ is he really in a zone or is this just the kind of performance we expect to see on a statistically determinable basis? When a guy drains 7 of 8 from downtown is this something special, something transcendental or merely an event that will pop up with predictable frequency?
People who play sports or follow them with any passion swear these effects are real. Basketball coaches issue instructions: “Get Joey the ball; he’s got the ‘hot hand’.” Baseball managers manipulate their lineups to get the guy with the ‘hot bat’ an extra turn at the plate. Golfers enter extra tournaments when they think that they’re ‘striking the ball’ good. Poker pros play more hours or enter more events when they’re ‘running good.’ But is there really a hot hands phenomenon? Are bats really hot? Do poker players really run good? Maybe. Then again, maybe not.
The psychologist Amos Tversky took a look at this issue some years back. He reasoned that if Joey really had a hot hand, then we should see a statistically aberrant performance, one where he made more shots with more regularity than his norm. So Tversky analyzed every shot taken by several dozen NBA basketball players over a full year looking for evidence of a hot hands effect. He found little. Players got ‘hot’ about as often as a random number generator got ‘hot.’
If Joey’s a 42% shooter, we expect to see runs of shots made and shots missed – and we can calculate just how long they should be, distributed over the full year. If another player makes 47% of his shots we should see a different pattern but one consistent with his level of skill. And this is what Tversky found. Sure, there were occasions where Joey hit nine in a row and seemed to be ablaze for an entire half. But these rushes happened about as often as we would expect given that Joey is, overall, a good player who makes a tad better than forty percent of his shots from the floor. So, no hot hands.
Other psychologists did similar analyses in a host of sports and found pretty much the same thing. Quarterbacks got hot about as often as their long term statistics suggest they should. Sure an all-pro like Tom Brady seems to have the hot hand more often than a journeyman backup but, statistically speaking, he should.
But as usually happens in science, when a topic is interesting people do deeper analyses. Follow-up studies suggested that there might be something that Tversky missed. Long runs of baskets or completed passes or shutouts in hockey were occurring more often than one might expect, statistically speaking. But, and here’s the fun part, it wasn’t clear what was causing them. It’s difficult, if not impossible, to tease apart a real hot hands moment from the belief that others have that one is occurring because the latter can produce the former.
If Joey seems to be on fire and if his team mates believe he’s got the hot hand, their behavior changes. They start setting effective picks, trapping opponents allowing him to get free, passing to him in optimal spots on the court. The likelihood of Joey continuing to make shots goes up and his stats defy expectations.
Do we want to conclude that Joey really had a hot hand or that everyone else, by virtue of their beliefs, changed how they play so that it looked like he did? If the hot hands effect is real it’s likely based on a conspiracy of beliefs of the participants.
I like Miami but not at 1-3, no matter how ‘hot’ LeBron is….