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Comment by slg | Hacker News Reader

These type of articles never take into consideration the reason why coaches don't go for it as often as a computer might. The coaches face a reverse moral hazard when taking risks because the negative outcomes are multiplied for them. Even if the statistics support their decisions, a coach will be fired for taking too many risks and failing. Is gaining an extra 2% (or whatever) in expected returns worth the risk of losing everything if the low(er) percentage outcome does actually happen? It is the same idea behind the whole "no one gets fired for buying IBM/Microsoft".

Until you get a coach's motivations more in line with the motivations of the team, you won't get a coach that is as aggressive as these computer simulations suggest they should be.

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I think there's selection bias in the underlying data. The dependent variable (realized success on attempted 4th down conversions) is conditioned on 4th down attempts by coaches.

Since coaches are conservative, they're likely to go for fourth down conversions only in cases when they are likely to succeed (due to defensive mismatches, etc).

Hence the model may over-estimate the benefit of going for it on fourth down.

Moreoever, the probabilities are likely to change if behavior changes. For example fakes or trick plays become less successful if you do them often.

People always say this, but it is actually true? Has any coach ever been fired for missing too many fourth downs?

I can't think of one off the top of my head. Mike Smith was under a lot of pressure a little while back for his aggressive decisions on 4th down (that were statistically correct IIRC) but wasn't actually fired.

However, the obvious counter to your question is how many coaches really go for it frequently on fourth downs? Most coaches just follow the conventional wisdom unless they are already in a desperate situation like Ron Riviera or they have built up a lot of good will like Bill Belichick.

So it sounds like fans and the media need to grasp EV first before coaches will be allowed to take the appropriate risks.

Not even missing too many. Just missing more visibly, compared to coaches with equivalent records.

Ask Nick Saban how trying to kick a field goal with 1 second left in the Baylor game is working out for him. There are plenty of people saying that any other coach would be fired.

Nick Saban can call any number of schools right now and be the highest paid coach in NCAAF. He has a reputation for going for it on 4th down and taking risks. Also, it was Auburn, not Baylor.

That particular outcome had happened less than 5 other times in the history of the modern NCAA. 99/100 times that game ends with either an Alabama win or O.T.

He hardly made a controversial decision.

The bar that I was watching the game in exploded when that happened. You wouldn't believe the number of people calling him all sorts of names for making that call. And, I think it was a good call too. The point is that being risk averse is the right way for a coach to keep his job.

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