Click to see larger chart.
I just spent a Sunday mostly watching football. It wasn't as much fun as it might have been. My poor 49ers show signs of life, but haven't reached respectability yet -- and the Raiders are flat out pathetic. Both teams lost ignominiously.
But the day's dissipation reminded me of a set of statistical calculations that I read about last spring in Kevin Drum's blog. With the support of the chart above, he writes:
On the evidence that I saw today, Art Shell might have been aware of this advice -- the Raiders tried to convert on several 4th down situations well outside the normal conservative practice. Mike Nolan took a more conventional approach with the 49ers, punting the ball away.
I'm sure the mathematical probabilities laid out in these studies are true -- but it is pretty easy to imagine how coaches actually make with these decisions and they seem to evaluate other variables. Today, it looked like Shell decided repeatedly to go for it because he considered his team already screwed -- just maybe if they succeeded at an unexpected 4th down conversion, they'd wake up and play like they meant it. Meanwhile, Nolan is trying to normalize the 49ers -- he doesn't want them shaken up; he is teaching consistency of play.
In any case, the statistical calculation misses what certainly is one of a coach's most important considerations in deciding to go for it: if the attempt goes wrong, he's the one who is going to face raving fans and possibly an angry owner. Usually it is the player who drops the ball who gets the vilification, but in this situation the responsibility for an unconventional risk falls directly on the coach. That's not something most coaches can afford to assume. Probably the ones most able to afford the risk are those whose teams least often force them to make a decision whether to punt or go for it.