Comments on Advanced NFL Stats: The 4th Down Study - Part 2

Yes, penalties are included. And to the extent blo...

2011-07-29T09:09:22.252-04:00

Yes, penalties are included. And to the extent blocks cause a missed FG, they are included. But the potential for a large return following a block is not included. This means that the case for going for it is very slightly stronger than described here, all other things being equal.

You haven't taken into account blocked punts a...

2011-07-29T04:48:31.007-04:00

You haven't taken into account blocked punts and fg's and the outcome of those, have you? What about penalties that result a 1st down?

What most people don't know, but should is tha...

2010-08-28T04:05:59.111-04:00

What most people don't know, but should is that football is like a coin that has two sides. Everyone knows the universal truth of the first side of the coin that says that a team that scores more points than the opponent always wins. What people don't know is how a team lost a game without factoring the score. The other side of the coin would say that the team with the most real turnovers always losses the game. Statisticians do not count all events that turn the ball over without first scoring atleast 6 points. If they did they would see that the team with the higher number always losses. Try this with any game and you will see that it works:

Complete Turnovers: Interceptions, fumbles lost, missed fg's, punts, 4th down fails, kickoffs lost, safeties, and turnovers due to time (given if the team in possesion at the end of the half failed to score and has to kick to start the second half. Not counted if another turnover half or whole occurs at the same time. Also when the game ends and the team trailing fails to score before the time expiresn not counted against the team with the lead. also nullified if another turnover takes place.

Half Turnovers: Failed extra point or 2pat, Successful field goal, 2point conversion allowed.

i think your math calculation is wrong. should be ...

2009-11-17T23:52:59.591-05:00

i think your math calculation is wrong. should be 1.75 Ep

Ben, that's a valid criticism. I assumed linea...

2009-11-06T10:18:57.847-05:00

Ben, that's a valid criticism. I assumed linearity for simplicity's sake. Part of the goal is to be able to convince non-stat guys, so simplicity is important. Perhaps I can add the full distributions to the analysis in a future edition. Thanks.

I just was linked from TMQ so that is why I am com...

2009-09-23T01:11:12.668-04:00

I just was linked from TMQ so that is why I am commenting a week late.

When you say "a punt from a team's own 40 (60 yds from the end zone) nets around 37 yards, giving the opponent a 1st down at their own 23. This corresponds to 0.5 EP for the opponent, which is -0.5 EP for the punting team," are you just using the straight average net punt yardage from a team's own 40? I don't know how drastically this would affect your values, but for a more rigorous calculation you would need to use the probability distribution of net punt yardage to calculate the EP of a punt from, say the team's own 40.

For a simplisitic example, when punting from your own 40, if there were a 30% probability of a net of 45 yards and a 70% chance of a net of 30 yards, then your EP would be -(.3 * (EP from your own 15) + .7 * (EP from your own 30)) which would not equal the EP of the average (EP is not linear).

Again, I don't know if you did this calculation behind the scenes, or if there simply isn't enough data to generate comprehensive distributions from every yard line (I would think there probably is, given the number of coaches who punt from inside opponents' territory).

Jeff-You are so right about the hindsight bias. J...

2009-09-15T23:46:17.054-04:00

Jeff-You are so right about the hindsight bias.

James-This type of analysis is for "normal" football situations, when neither team has a large lead and the clock is not a factor. We need to use a WP analysis for other situations. I'll address that issue in future posts.

Belichick has so much credibility and reputation for being ahead of the game, he'd be the one guy who could pull it off.

By taking away 0.7 EP for a kickoff after a succes...

2009-09-15T17:05:53.418-04:00

By taking away 0.7 EP for a kickoff after a successful score, this assumes there is sufficient time left on the clock for a drive by the opposing team. Will you look at how little time needs to be left in a half for this to change the EP? For example, the Chargers only needed 40 seconds to score a field goal before the half last night against the Raiders (although that was largely a result of Sproles 59-yd kick off return).

Also, Belichick and the Pats went for it on 4th down twice early in the game against the Bills. In the end they still won, but do you think that even an established coach like Belichick with a tendency for 4th down attempts would have taken some heat if the Pats lost?

This is a great post. I've seen so much acade...

2009-09-15T15:41:47.519-04:00

This is a great post. I've seen so much academic research on this topic and all of it says that coaches should go more often. I have yet to read one study that mathematically defends the status quo.

I realized something else yesterday listening to the announcers who were former coaches (particularly Gruden and Billick). There is an enormous amount of hindsight bias in the football community. On at least four different occasions I heard "The coach is making a mistake here. He shouldn't be doing this. [play works] Wow, what a great call. He obviously is a genius. He was so smart to make that call there"

Just one example:

Gruden said he'd kick the onside at the end of the game. Belichick kicks away and gets an extraordinarily lucky fumble. Gruden compliments Belichick on "knowing" the regular kick would work.

***side note I wrote a really long post on the Hawk n Dove page about that call.

I wish announcers would be a little more upfront with the fact that the mathematically correct call doesn't work all the time and that the incorrect call sometimes gets lucky.

I also think we should note that the most egregious 4th down mistakes always come in a situation where the team is likely to lose either way. Going for it might increase the win prob from 15% to 20% but the coach knows that there is still an 80% likelihood he is going to have a bunch of people second guessing his decision. Although its absurdly selfish, he'd rather avoid that than gain an extra 5% WP.

If somebody in the mainstream media would just explain to casual fans the math involved in this, I think it would start to change. Then again, most Americans hate math and they'd rather avoid it in their free time.