Wednesday, December 14, 2005

Does Icing the Kicker Work?

My helmet is equipped with a tiny face mask
What it possibly could protect I do not know
The other guys on the team like to make fun
of my little shoulder pads
And also like to hide the special shoe I need to kick in the snow

People think it's so easy
To kick a field goal from the 30 yard line
They forget to add seven yards for the snap
And 10 more 'cause the goal posts are pushed way back

In 1974, the uprights were right on the goal line
But some of the players were running into them and getting hurt
So screw the kicker
Who cares about the kicker?

The NFL has a long and storied tradition of "icing" the opposing team's kicker: when the other team and kicker line up for a field goal at a crucial moment, calling a time-out to force the kicker to back down from his position and attempt to stay loose but ready for two minutes. Anecdotal evidence suggests that this treatment might just be a waste of a time-out:

Cincinnati's Shayne Graham said the effect of being "iced" is negligible. He is 3-for-3 on game-deciding kicks over the last three seasons, and last Sunday made a 37-yarder on the final play to beat Cleveland. In that game, the Browns had run out of timeouts, but the Bengals stopped the clock with 1 second remaining.

"I can kind of understand the thought process of the way they do it, but I really don't know that I've ever seen it work — not just myself, but other teams," he said. "I've had it done to me almost every game-winner I've ever had. In high school and college and pro, it's happened every time. I don't think it's had any effect on it."

Graham and [New York Giants kicker Jay] Feely agreed the extra time would have little impact on a veteran kicker, but that a younger kicker might succumb to jitters.

"For a young kicker, time can be a dreaded commodity," Feely said. "They don't want that time to think and worry about the implications. The biggest thing is just to focus on the present."

Link (via Fark). Statisticians, however, believe it can work:
Using this model, [Scott] Berry and [Craig] Wood obtained results using the 2-season data that matched certain expectations. A kick made indoors is more likely to be successful. Clouds also have a small beneficial effect on kicks. Rain or snow, on the other hand, reduces the chances of success. High winds also reduce the probability of success, but not as much as rain or snow.

In pressure situations, the odds of success change very little (a mean decrease of 1.8 percent). However, icing the kicker in such a situation has a pretty strong negative effect.

Using their model, Berry and Wood calculate that, for an average kicker, the estimated probability of a successful 40-yard kick in sunny weather is 0.759. The estimated probability under the same conditions for an average kicker who has been iced is 0.659.

"Reducing the probability of a successful kick from 0.759 to 0.659 is a very important difference," Berry and Wood report.
Link. Unfortunately, either these statisticians or the journalist covering them forgot the one important precept I recall from Statistics 101: correlation does not equal causation. There's a chance that the reason the rate is lower for kickers who have been iced is some confounding factor, like the youth of the kicker, that makes it more likely both that the opposing team will call a time out and that he misses the field goal. The jury is still out.

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