Comments on Advanced NFL Stats: Year of the Run Defense?

Oh, never mind, I noticed someone said exactly the...

2009-11-29T11:52:30.353-05:00

Oh, never mind, I noticed someone said exactly the same thing above.

I'd wager that teams run the ball quite a lot ...

2009-11-29T11:51:20.725-05:00

I'd wager that teams run the ball quite a lot more in the playoffs, partly due to weather, and partly due to job security.

I doubt any coach wants to have his team employ a high variance strategy - and fail - in a huge game. We already see this kind of effect with the whole 4th down issue, but it's magnified in the playoffs. So in turn you have more emphasis on "old school conservative football", which means run offense and run defense are of incredibly high importance.

Interesting point about the "loafs."

Yes, o...

2009-01-14T22:55:00.000-05:00

Interesting point about the "loafs."

Yes, of course turnovers are crucial in any particular game, playoffs or not. That's obvious in retrospect. I'm trying to figure out what stats are predictive.

I can tell you with assuredness that the speed of ...

2009-01-14T22:31:00.000-05:00

I can tell you with assuredness that the speed of the game DOES go up a notch, simply because there are absolutely no loafs by a player. During the regular season every player is graded for various aspects of their position. One of the details that is graded on every player is a "loaf", and it means just that. They didn't go "all out" so to speak. During the playoffs, I can assure you that there are NO "loafs" on anyones sheet the next day.
Couple that with the fact that teams tend to run the ball more in the playoffs due to weather and wind factors, not to mention that a team absolutely has to be two dimensional in their offense to be effective in the playoffs. It is why the AZ team is all of a sudden successful in the playoffs. They have run the ball more to offset what was basically a pass only offense, and they have definitely been able to stop the run better than they did during the regular season.
I would suggest that while a Good rush D is essential ingredient to contributing to a playoff win, you really will find that the real contributing factor to winning in the playoffs is not turning the ball over.
Officiating is also a factor and they do tend to let them play a little by not calling a lot of holding penalties, but as far as letting them go in the passing game.....ain't happening. They will call pass interference and defensive holding on pass plays.
I believe we can find the same statistic that you found on Rush D 7/8 winners is exactly the same # as it pertains to turnovers.

I wonder if officiating might play into this.
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2009-01-14T13:33:00.000-05:00

I wonder if officiating might play into this.

It is my feeling (with absolutely no evidence) that in the playoffs the refs are more likely to Let'em play.

This means fewer holding calls (advantage for both run and pass, not sure wich is greater) and less pass interference calls clearly a disadvantage for pass offense. So if you are a good run defense already your pass defense might get better automatically in the playoffs due to officiating. Just thinking off the top of my head.

Also, and you may have allready done this, it would be interesting to see how playoff game look statistically compared to non playoff games.

Number of plays, number of runs vs pass, average yards, scoring etc. That might give you a feel for how playoff games develop compared to regular season games

If the rate of injury is stat. significantly highe...

2009-01-13T17:05:00.000-05:00

If the rate of injury is stat. significantly higher during the playoffs than typical late-season games that would offer evidence of increased "intensity"...i.e. players hitting harder, yada, yada. Restrict it to warm weather and dome games to eliminate the snow (haha now lets talk about small sample)...............Can't wait for the Boss half-time show.

how about comparing the stat (run D) during the re...

2009-01-13T14:43:00.000-05:00

how about comparing the stat (run D) during the regular season restricted to playoff teams playing other playoff teams.

It may be that run D is more important playing against a good opponent (or a good oponent with a good run game), whereas it is not important when you are playing a lousy team.

-bob

bytedodger-Small sample size is always a problem w...

2009-01-13T12:22:00.000-05:00

bytedodger-Small sample size is always a problem with playoffs. That's the reason I looked at 'playoff-caliber' regular season games. But it turns out there are differences between those classes of games too. I've got a couple more years of data (22 more playoff games) since the original study, so when I have time I'll compile the data and see how the effects hold up.

Odysseus-Good question. I used end of year ranking...

2009-01-13T12:18:00.000-05:00

Odysseus-Good question. I used end of year rankings, not 'to-date' stats to compare teams.

I hear people talk about the intensity of the playoffs a lot, and the stakes are certainly very high. But I wonder how that really changes the game. Do players really hit harder, etc.? Is that even possible? Players might claim that, but are those just words given the high stakes? Is there objective evidence of increased physicality or changes in the refs' dispositions?

I agree conservative play is a plausible theory for what we observe here in comparisons of playoff winners. But I don't have any direct evidence.

Odysseus your dead bang on your comment maybe what...

2009-01-13T12:00:00.000-05:00

Odysseus your dead bang on your comment maybe what matters is that your run defense is "good enough" rather than simply "top ten". As you advanced towards the superbowl, balance is critical so you also have to have a good offense to take the pressure off even the best of defenses.

Thank you, Anonymous. I missed one. MIN lost to PH...

2009-01-13T11:22:00.000-05:00

Thank you, Anonymous. I missed one. MIN lost to PHI but had the better def run eff. I've corrected the article to say 7 out of 8.

Here are a few other questions: during the season,...

2009-01-13T10:56:00.000-05:00

Here are a few other questions: during the season, are you using a teams run defense rank from the end of the season (after looking at their whole body of work) or updating the rank after each game as we get more data? It might clear up the information a bit if you use end-of-season rankings as those are more accurate.

Also, consider that players playing the playoffs are trying harder than the regular season. Think about it, intensity and physicality go up in the playoffs, the refs are less inclined to alter a game with borderline penalties, players are typically more experienced, more veteran, better able to get away with physical play.

Coaches don't want to "get fancy" and risk losing their job because of poor play calling. Remember: conservatism is rewarded in the NFL by owners and fans alike. Its much easier to blame the offensive line if you get stuffed on 4th and 2 than to blame them if you try a halfback pass on 4th and 2 and the fan base calls for you to be fired because of a single bad outcome in a special play.

@bytebodger

I had the similar problem with ...

2009-01-13T10:43:00.000-05:00

@bytebodger

I had the similar problem with my NBA model. I trained my model on the last 5 years of data. Then for the current year, I split the set into a validation set and a prediction set. In my model I remove any games between teams that have not played 15 games. The validation set is all the games between teams that played at least 15 games but less than 30 games. So with the validation set I can see if my model will perform well or not. It is not 100% sure but at least it gives you an idea of your model future performance.

Part of the problem when analyzing statistics over...

2009-01-13T10:41:00.000-05:00

Part of the problem when analyzing statistics over a long period is changes in the way statistics are measured.

This doesn't have as big of an effect in football but in basketball, who gets credited with assists, steals, and some rebounds are depending on the scoring table and changes in how they are perceived.

The other major thing I'd point out is the *absolute* strength of a team's run defense. Some years the best run defense in the league might be (if it were transported through time) only the fifth or sixth best in the league now (or vice versa). So maybe what matters is that your run defense is "good enough" rather than simply "top ten". The first term is an measure of absolute skill, the second a relative term.

It's possible that because the average playoff gam...

2009-01-13T10:21:00.001-05:00

It's possible that because the average playoff game takes place in worse weather, the ability to stop the run has a greater impact. Aside from that, I'd guess it's statistical noise.

How can this year be 100% playoff win percentage w...

2009-01-13T10:21:00.000-05:00

How can this year be 100% playoff win percentage when Minn has the best DRUN rate?

Your analysis highlights what is so maddening abou...

2009-01-13T09:30:00.000-05:00

Your analysis highlights what is so maddening about the statistical analysis of football - especially the analysis of PLAYOFF football. The sample sizes are so small that you must constantly second guess your own conclusions. If you continually expand your data set by going further back in time, you then run the risk of invalidating your own conclusions because, after a certain period of time, the very nature of the game itself evolves and the data is no longer applicable.

This problem has been outlined for me when doing regression analysis on NBA games. For example, there are 1,230 games in the NBA regular season so you might think that ANY statistical trend that is consistent throughout the length of an entire NBA season is in fact a valid trend, right? Wrong. I have found certain algorithms that yield stunning accuracy for the length of an entire NBA season, or for two consecutive seasons, but then crash entirely in subsequent seasons.

And if seemingly-valid trends materialize and then evaporate over the course of thousands of NBA games, then it must be much more difficult to accurately identify trends that materialize over the course of merely dozens of NFL playoff games.