It is playoff time in the National Basketball Association. After a seemingly endless season, the players are finally getting down to business. You would think that NBA players who have spent their lives playing in front of crowds and who claim to live for the thrill of the playoffs would be immune to pressure. But are they?
My colleagues Darrell Worthy, Todd Maddox and I have been interested in choking under pressure, so we decided to figure out whether NBA players show any signs of choking. The results of our analyses were published in the April, 2009 issue of The International Journal of Creativity and Problem Solving. The easiest way to look for signs of choking under pressure is to look at free throw shooting. For those of you who aren't basketball fans, a free throw is an unobstructed shot a player is given from a line 15 feet from the backboard. Because every free throw is taken from the same distance, it is a useful way to look at choking under pressure.
We found game transcripts for every NBA game played in the 2003-4, 2004-5 and 2005-6 seasons (including the playoffs). We looked at every free throw taken in the last minute of a game when the teams were within 5 points. So, we only considered close games.
The difficulty with looking at free throws shot in different situations, is that it is possible that different players will take the free throws depending on the situation. For example, if a team is ahead by 2, the opposing team may try hard to foul the worst free-throw shooter to increase their chances that the player will miss. So, we compared the percentage of free throws made for each point difference between teams to the average percentage of the free throws made by those players across the whole season. If the shooters are below their season average, then they are choking under pressure. If the shooters are above their season average, then they are excelling under pressure.
So, what happened? The highest pressure situation is probably when a player's team is down by one point, because making the free throw will tie the game. In this situation, players made around 69% of their free throw. Overall, these players made about 76% of their free throws during the season, so they shot much worse when their team was down by 1 than they did overall. This difference was statistically reliable.
Now, just seeing this number, there are lots of possible explanations. Perhaps players are just tired at the end of the game, and so they tend to shoot worse. A good comparison case is what happens when the teams are tied. This situation is much less pressure-packed, because even if the player misses the free throw, the game is still tied. The player has the chance to be a hero, but without the risk of failure. In this case, the players made about 78% of their free throws. These players also tended to make about 76% of their free throws overall, so they were actually slightly above their season average for this shot (though the difference was not statistically significant).
Looking more broadly at the data, players were statistically worse than their season average when their team was down by 2 points (72% made compared to a season average of about 77%), and when their team was up by 1 point (also 72% compared to a season average of a about 77%). When the teams were separated by 3 or more points in any direction, the players shot free throws at about their season average.
So, it looks like NBA players also choke under pressure, and that this effect is strongest when the player has the chance to tie the game in the last minute. In some ways, this kind of result should be a relief to all of us. One added stress of being in a pressure situation is the belief that we will perform badly, even though others would not be that strongly affected by pressure. But even elite athletes at the top of their game suffer the effects of performance pressure. So, relax, the worst thing that can happen to you when you're under pressure is that you'll be just like everybody else.