Comments on Advanced NFL Stats: Belichick 4th Down Follow-Up

Hey another long pass on short yardage during mon ...

2009-11-25T14:20:35.052-05:00

Hey another long pass on short yardage during mon nite football.

I think it was 1.09 left in 3rd quarter and they threw a legitimate long pass on 3rd/one.

Dont tell me that no one covers long passes on short yardage plays. It happens every week in the NFL.

Brian, thanks. Per my explanation above, ideally ...

2009-11-24T21:44:09.977-05:00

Brian,

thanks. Per my explanation above, ideally we should strip out "failed" attempts due to offensive penalty and apply that percent of total attempts to the probability of Colts scoring after Pats punt from 5 or 10 yards back (weighted average or just 7.5 yards back if probably close enough), rather than lumping in that category of results with actual failed attempts and

Yes, offensive penalties are included too as long ...

2009-11-24T20:18:38.431-05:00

Yes, offensive penalties are included too as long as they occur during the play. Pre-snap penalties are not included, and any other penalty between plays, because there is still the option to punt following the penalty.

Brian, It sounds like you are saying that conversi...

2009-11-24T19:27:01.133-05:00

Brian,
It sounds like you are saying that conversion via Defensive penalties are included in your data. Are Offensive penalties included, too (i.e., offensive penalty during the play such as holding)?

To elaborate on my comment above and lay out the a...

2009-11-23T20:59:59.179-05:00

To elaborate on my comment above and lay out the algebra and an illustration:

If "failing" with (i.e., due to) offensive penalty were not a possibility, for Pats to LOSE after going for it, two things would have to happen, (1) Pats fail to convert, and (2) Colts TD starting from Pats 28. So, if P (fail) = 0.42 and P(Colts TD from Pats 28) = 0.53, than P(Pats losing if go for

Additional notes re: penalties: - Converting with...

2009-11-23T18:11:09.479-05:00

Additional notes re: penalties:

- Converting with Defensive penalty should be considered equal to converting without Defensive penalty, because result is the same.

- Optimal equation for WP in Go For It scenario would consider probability of converting, probability of failing without penalty applied to probability of Colts scoring from Pats 28, and probability of "

If I set up this Google doc correctly and pasted t...

2009-11-23T17:14:20.477-05:00

If I set up this Google doc correctly and pasted the link correctly, at this link http://spreadsheets.google.com/ccc?key=0Am3TwX_gP-RCdHk1dDhFNmlNQ3FjQ1EyaWxxY29jMHc&hl=en is a spreadsheet tool I've created that anyone can use to plug in your own assumptions (and tinker with them) to assess Punt vs. Go For It.

Typo: I meant to say punting after Offensive penal...

2009-11-23T16:00:35.281-05:00

Typo: I meant to say punting after Offensive penalty would mean Colts ball on own 32 or 37.

Brian, Re: penalties, we have 4 categories: 1. Con...

2009-11-23T15:55:48.390-05:00

Brian,
Re: penalties, we have 4 categories:
1. Convert without pentalty on Defense.
2. Convert with penalty on Defense.
3. Fail without penalty on Offense.
4. "Fail" with penalty on Offense.

Including penalties on Offense in the final figure, thus including it as a factor in the weighted average of conversion percentage (probability) artificially

The data I have comes with a code for any play tha...

2009-11-23T15:10:38.034-05:00

The data I have comes with a code for any play that makes a first down. It says P if it was a passing play, R if it was a run, and X if was a penalty. So yes, 1st downs by penalty are considered in the data, but only if the penalty happened on the play. Penalties between plays do not factor in.

Brian - You mention stats that most people see on ...

2009-11-23T15:03:06.235-05:00

Brian - You mention stats that most people see on nfl.com and espn.com may not include 4th downs converted via penalty. On the other hand, do the stats in which you rely on, include offensive penalties on 4th down conversion attempts as failed attempts? Should they be included and if so, is it possible to get an adjusted sample?

Edward -- thanks.

2009-11-22T23:49:32.451-05:00

Edward -- thanks.

"Also, what about factoring in cost of losing vs t...

2009-11-22T22:44:55.834-05:00

"Also, what about factoring in cost of losing vs the benefit of winning? Given the playoff implications, I think you assign a very high cost to losing here. In other words, a win gives the Patriots marginally improved playoff prospects from an already good position. A loss causes a significant hit to their playoff prospects."

If you're concerned that the cost of losing is

Gordon: http://www.nfl.com/teams/statistics?team=...

2009-11-22T20:16:16.748-05:00

Gordon:

http://www.nfl.com/teams/statistics?team=ARI

Repeat for all 32 teams and add up the results (which by now have been updated to include today's games).

Brian -- Can you please provide a link to your sou...

2009-11-22T18:26:29.198-05:00

Brian -- Can you please provide a link to your source for that 4th and 3 or less data for the NFL in 2009?

Edward -- Can you do the same for your source for ALL 4th attempts in NFL in 2009?

thanks

Edward and Brian, Thanks for the correction re: 2...

2009-11-22T17:16:40.539-05:00

Edward and Brian,

Thanks for the correction re: 2009 4th and 3 or less (assuming you're correct). As I said, the figure I presented was from a friend. I didn't verify it, so if it's incorrect, my apologies.

Dr. Duru, First, everyone knows that the statisti...

2009-11-22T15:27:28.464-05:00

Dr. Duru,

First, everyone knows that the statistics discussed here are estimates. We'll never know the "true" probability of winning via going for it on fourth down, but neither will we ever know the "true" probability of winning via punt. There is no reason that punting should be considered the "safe" option. That being said, the 9% edge that going

Sorry! I just realized that the cost of losing vs ...

2009-11-22T12:58:42.177-05:00

Sorry! I just realized that the cost of losing vs winning is probably immaterial in your analysis! You just want to increase the chance of winning, period.

Your two posts did not address whether the nine pe...

2009-11-22T12:56:53.975-05:00

Your two posts did not address whether the nine percentage points is significant enough to warrant going for it. Also, what about factoring in cost of losing vs the benefit of winning? Given the playoff implications, I think you assign a very high cost to losing here. In other words, a win gives the Patriots marginally improved playoff prospects from an already good position. A loss causes a

One other thing. The data most people see, like on...

2009-11-22T09:34:37.797-05:00

One other thing. The data most people see, like on nfl.com or espn.com, may not include 4th downs converted via penalty.

Yeah, that 2009 4th down data someone posted is wa...

2009-11-22T09:32:17.619-05:00

Yeah, that 2009 4th down data someone posted is way off. If we just take 2009 (which I still think is a bad idea) for all 4th and 3 or less, the conversion rates are 107 for 183 (58.5%).

That includes attempts inside the red zone and on the goal line, which would be more difficult than the 4th down we're discussing. There have only been 27 4th and 2s outside the red zone this year.

Gordon: I just checked NFL.com's stats for each t...

2009-11-22T01:54:26.594-05:00

Gordon:

I just checked NFL.com's stats for each team, and assuming I'm not an idiot, NFL teams are 146-for-304 (48%) on *all* fourth downs in 2009 (up to and including Thursday's MIA-CAR game).

Gordon: Your estimates would be reasonable. I'm ...

2009-11-22T01:19:48.414-05:00

Gordon:

Your estimates would be reasonable.

I'm still puzzled that the 4th-and-3 or less rate from the first half of 2009 would be so low, though. Brian has 9 seasons of data vs. 1/2 a season (18 times as many games), so one figures that he'd have around 18/3 = 6 times as many plays in his 4th-and-2 figure. Maybe only 4x as many if we think that 4th-and-2s make up

Good question. The recency of the data is far less...

2009-11-22T00:44:49.706-05:00

Good question. The recency of the data is far less important than the size of the data set. QUOTE: "If we constrain ourselves to looking at just 1 (or less) season of data, we're going to have a very large sample error. There just aren't that many 4th and 2s where teams go for it...."

I love it how you purport to be all logical with your analysis of this and then

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2009-11-22T00:41:44.260-05:00

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