## MatheMUSEments

Articles for kids about math in everyday life, written by Ivars Peterson for Muse magazine.

## June 17, 2007

### Icing the Kicker

There are just a few seconds left in the football game. Your team is all set to kick a field goal to win. The opposing team, however, calls a timeout. Its players hope that the extra time will make your kicker think about his upcoming kick—and then miss the field goal. The strategy is called "icing the kicker."

But does this time-honored trick really work? Does making a kicker wait an extra minute or two increase his chances of missing a crucial field goal?

That's not something you can find out directly. You can't let a kicker try a field goal right away and then let him try the same field goal after a delay (or vice versa) and see what happens. Instead, statisticians have to look at data from a lot of games to see if they can detect a difference.

A variety of factors might affect whether a field-goal try is successful. It could depend, for example, on how skilled the kicker is, the length of the kick, the score when the kick is made, and the amount of time left in the game. With that in mind, statisticians Scott Berry and Craig Wood recorded data on all field-goal attempts during the 2002 and 2003 National Football League seasons (including playoff games). They even noted whether the turf (grass or artificial) turf and, for outdoor games, the weather conditions (sun, clouds, rain, average wind speed, temperature).

Taking all these factors into account, Berry and Wood found that icing works. During the last 3 minutes of a football game, a kicker has a somewhat smaller chance of making a field goal if he has to wait and has time to get nervous.

So, at least one piece of sports lore holds up to scrutiny. I'm not so sure about the one about double numbers on a player's jersey bringing good luck, however.

Muse, September 2005, p. 27.