Wednesday, March 4, 2009

The Inevitability of Errors

Errors are inevitable – no matter what the stakes, no matter how much you practice, things are going to go wrong a certain percentage of the time in any complex task or decision. The New York Times has an article with an excellent example: basketball free throws.

There is nothing in sports as straightforward as a free throw; the equipment is always the same, the geometry is constant, and there is no defense interfering. The only variables are the player’s concentration and control over his or her body. And yet, at the highest level of the game, it goes wrong 25% of the time, year after year after year:

In the National Basketball Association, the average has been roughly 75 percent for more than 50 years. Players in college women’s basketball and the W.N.B.A. reached similar plateaus — about equal to the men — and stuck there.

The general expectation in sports is that performance improves over time. Future athletes will surely be faster, throw farther, jump higher. But free-throw shooting represents a stubbornly peculiar athletic endeavor. As a group, players have not gotten better. Nor have they become worse.

“It’s unbelievable,” Larry Wright, an adjunct professor of statistics at Columbia, said as he studied the year-by-year averages. “There’s almost no difference. Fifty years. This is mind-boggling.”

And it’s not like the stakes aren’t high:

Last season, Memphis was 38-2 despite making only 61 percent of its free throws, missing an average of nearly 10 a game. The Tigers lost the national championship game after missing 4 of 5 free throws in the final 72 seconds against Kansas, which had made a late 3-point shot to tie the game and won in overtime…About two-thirds of a winning team’s points in the final minute typically come from the free-throw line…

Obviously, we need to work to eliminate mistakes and design systems to minimize the chance of them occurring. But, a certain percentage of the time errors will happen. Learn what you can from them and move on.