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11/18/2009

Bill Belichick's decision

When I saw it unravel on TV, I had two reactions:
  1. Speaking to myself: holy fuck, what the hell is he doing?
  2. Thinking to myself: that's a gutsy call... fuck Peyton Manning, we're going for it.
Wednesday after a Sunday, people are still talking about whether it is the right call or not. All the statisticians have came to Belichick's defense, while most sports personalities have been against.

I'm in the for-camp. I was chatting with my friend while the game was still going. Quickly throwing out these percentages on the top of my head:
  • Prob of converting 4th down: 50%
  • Prob of Colts scoring 7 from the 30 yard line: 90%
  • Prob of Colts scoring 7 for their own 30 yard line: 70%
So the Pats had a 55% of winning (50% + 50% * 10%) if they go for it. And 30% if they punted. So with the top of my head probabilities, Belichick was right. And that's not even adding the probability that the Colts score quickly, and Brady has the ball back to drive for a field goal in a minute.

Of course you can poke holes. The biggest argument that the anti-decision camp make is that you have to trust your defense to stop the Colts. Basically, they say the 70% is lower. Okay, let's examine: Peyton Manning just completed a 2 minute 80 yard touchdown drive (after a suspect pass interference call). He also has the 2 minute warning and a Colts timeout to use. If you're pegging his prob of success to be lower than 55%, I think you are greatly underestimating the QB. But hey, that's just me!

I think Steve Levitt says it best: it's a principle-agent problem with coaches. The probabilities are in the teams favor, but most coaches are adverse to taking risky decisions that are game changing.

2 comments:

The Pretender said...

Most of my thoughts are on this post from my blog: http://ramblingsandgamblings.blogspot.com/2009/11/big-weekend-in-sports-sport.html
but there are a few new things I've heard since.

1. Some fans think he showed too much trust in his defense. They think he thought, "if we make this 4th down great, if not, we'll stop them from the 30." Although, the fallacy in that theory is that if you think you can stop them from the 30, you should be able to stop them from 70.

2. CC pitched on three days rest for much of the playoffs. Rivera threw more 2 inning saves than he had in a long time. You go with your best when the game is on the line. Always.

3. If it wasn't for Belichick's decision, the last three days would have been filled with talk about the Pat's 4th quarter collapse instead. Took media pressure off the team.

4. People in general have sudden death aversion. I think you know that term. I've written about it but it was first published by Richard Thaler.

Josekin said...

#3: Maybe one day of Pats D talk. Funny that I did delete a paragraph I wrote about how the decision basically shifts the responsibility from the Pats D (already peed itself in the 4th quarter once) to the coach.