Sherman In A Nutshell | Page 2 | FinHeaven - Miami Dolphins Forums

Sherman In A Nutshell

nyashfan said:
Then it suggests that rushing attempt differential is correlated to winning because, all things being equal, more rushing attempts implies more rushing yardage. So today the Dolphins won the battle in rushing attempts and rushing yardage. Both must be more predictive than rushing YPC.

Is the correlation between rushing attempt differential and win percentage dramatically larger than rushing yardage differential and win percentage?
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0.71 to 0.62.
 
shouright said:
I noticed that as well, and I think part of the problem with that as well is that when you have a three-and-out on the basis of three passing plays in that sort of situation, it translates to a bit of a momentum shift for the team down on the scoreboard, because they're able to get the ball back with little time having been taken off the clock. It's as if you breathe a bit a life into them by giving them exactly what they need to feel like they have a fighting chance in the game -- a defensive stop with minimal time taken off the clock.

Compare that with a three-and-out on the basis of three running plays, in which a great deal more time would be taken off the clock, and/or the attainment of even one first down, which would do the same.

You have to run the ball there because you don't know you're going to get the first down to wind down clock, whereas you do know you can wind it down with running plays. At that point you've minimized the sort of momentum shift I'm talking about here.
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Agreed, but I'm not certain its Sherman who's predominantly preferring to pass in those situations. He may be getting overruled. I say that due to several comments Sherman made about play selection in the preseason. Just sayin'. Also, as you said to me earlier, there's the fact that Sherman did not have this tendency with other teams he's been successful with.
 
nyashfan said:
Among the ones I listed!

Turnover differential
3rd down conversion percentage differential
Rushing attempt differential
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I think TOP differential is what kept us in the game, despite a poor outing by the QB in the first half. The other statistics you're referring to contributed to that in a positive way, overall.
 
nyashfan said:
Thanks. Please read my prior post. I edited it after this reply.

Also, do you know the correlation between rushing YPC average and winning? Here, looking at team differential might be silly.
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0.28.

As for what you added above, how should we define "success"? I showed you the other day that the Dolphins' success rate in terms of one measure of it is no worse than the league average.
 
Shouright,

My purpose is not to challenge your assertion that the Dolphins' rushing "success" rate is near the league average according to the Football Outsiders DVOA. I believe you, I promise!!

My goal is to see if I can identify another statistic involving a team's rushing performance that correlates highly with winning percentage and is easier to interpret than is rushing attempt differential.

Saying it another way, I am trying to define rushing "success" without relying on either rushing attempts differential or Football Outsiders DVOA. The challenge at arriving at an alternative definition of rushing success is how/whether to quantify the impact of outliers.

You have stated that the correlation between average YPC and winning percentage is low. My hypothesis is that the reason it is low is because a high YPC can be inflated by a couple of large gains. My thought is that if a high YPC is achieved via a larger degree of consistency, it would be more predictive of winning percentage. Rightly or wrongly, my thought was that a large positive skewness could quantify a team's lack of rushing consistency for a given level of mean YPC.

A "naive" definition of skewness is to calculate (mean - median) / standard deviation across a team's set of rushing yards per play in a given game. This provides a way to quantify the extent by which the average YPC was inflated by a few large rushing gains. I understand that such an analysis would be cumbersome.

With respect to today's game, the Dolphins rushing game appeared dominant using the "eyeball" test as compared with the Jets rushing game, despite the Dolphins lower mean YPC. What peaks my curiosity is whether the Dolphins lower (apparent) skewness of the distribution of rushing yards across all such attempts can explain the perceived relative rushing dominance by the Dolphins.


shouright said:
0.28.

As for what you added above, how should we define "success"? I showed you the other day that the Dolphins' success rate in terms of one measure of it is no worse than the league average.
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nyashfan said:
Shouright,

My purpose is not to challenge your assertion that the Dolphins' rushing "success" rate is near the league average according to the Football Outsiders DVOA. I believe you, I promise!!

My goal is to see if I can identify another statistic involving a team's rushing performance that correlates highly with winning percentage and is easier to interpret than is rushing attempt differential.

Saying it another way, I am trying to define rushing "success" without relying on either rushing attempts differential or Football Outsiders DVOA. The challenge at arriving at an alternative definition of rushing success is how/whether to quantify the impact of outliers.

You have stated that the correlation between average YPC and winning percentage is low. My hypothesis is that the reason it is low is because a high YPC can be inflated by a couple of large gains. My thought is that if a high YPC is achieved via a larger degree of consistency, it would be more predictive of winning percentage. Rightly or wrongly, my thought was that a large positive skewness could quantify a team's lack of rushing consistency for a given level of mean YPC.

A "naive" definition of skewness is to calculate (mean - median) / standard deviation across a team's set of rushing yards per play in a given game. This provides a way to quantify the extent by which the average YPC was inflated by a few large rushing gains. I understand that such an analysis would be cumbersome.

With respect to today's game, the Dolphins rushing game appeared dominant using the "eyeball" test as compared with the Jets rushing game, despite the Dolphins lower mean YPC. What peaks my curiosity is whether the Dolphins lower (apparent) skewness of the distribution of rushing yards across all such attempts can explain the perceived relative rushing dominance by the Dolphins.
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I know you caveated the skewness measure but am curious if this formula is something commonly practiced. It's just interesting to see a "mean-median" calculation when one is used in parametric stats and the other in non-parametric stats. I'd be interested in any link to this use of the mean and median.

I'd also be interested if you guys have ever tried fitting any type of model to "winning/losing" outcome for the same data set that you are calculating the correlations from. Be interesting to see what a model "says" that gives you the optimal chance of winning. Good stuff here.
 
ATL_PHIN_FAN said:
Agreed, but I'm not certain its Sherman who's predominantly preferring to pass in those situations. He may be getting overruled. I say that due to several comments Sherman made about play selection in the preseason. Just sayin'. Also, as you said to me earlier, there's the fact that Sherman did not have this tendency with other teams he's been successful with.
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Which is why I want Philbin and Sherman gone. Philbin's system pretty much ignores the running game, and Sherman's playcalling often stalls what little momentum they do get when running the ball.
 
nyashfan said:
Shouright,

My purpose is not to challenge your assertion that the Dolphins' rushing "success" rate is near the league average according to the Football Outsiders DVOA. I believe you, I promise!!

My goal is to see if I can identify another statistic involving a team's rushing performance that correlates highly with winning percentage and is easier to interpret than is rushing attempt differential.

Saying it another way, I am trying to define rushing "success" without relying on either rushing attempts differential or Football Outsiders DVOA. The challenge at arriving at an alternative definition of rushing success is how/whether to quantify the impact of outliers.

You have stated that the correlation between average YPC and winning percentage is low. My hypothesis is that the reason it is low is because a high YPC can be inflated by a couple of large gains. My thought is that if a high YPC is achieved via a larger degree of consistency, it would be more predictive of winning percentage. Rightly or wrongly, my thought was that a large positive skewness could quantify a team's lack of rushing consistency for a given level of mean YPC.

A "naive" definition of skewness is to calculate (mean - median) / standard deviation across a team's set of rushing yards per play in a given game. This provides a way to quantify the extent by which the average YPC was inflated by a few large rushing gains. I understand that such an analysis would be cumbersome.

With respect to today's game, the Dolphins rushing game appeared dominant using the "eyeball" test as compared with the Jets rushing game, despite the Dolphins lower mean YPC. What peaks my curiosity is whether the Dolphins lower (apparent) skewness of the distribution of rushing yards across all such attempts can explain the perceived relative rushing dominance by the Dolphins.
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And all that makes sense, but I think the measure you're after, despite the fact that it's theoretically sound, would pale in comparison in sophistication to what's expounded on the Advanced NFL Stats website with regard to rushing success rate, in terms of how its defined by positive expected points added.

Sometimes other people have already done the work for us. ;) :up:
 
http:// http://en.m.wikipedia.org/wiki/Nonparametric_skew

I asked Shouright if there is a public database to download in order to do analyses and he didn't think there was. I think he gets pre-aggregated data from Football Outsiders and then does his own correlations.

The motivation behind using the (mean - median) / standard deviation definition of skewness is that its domain is from -1 to +1. It is thus interpretable in a similar manner to a correlation. See attached link.

I have never seen skewness used for anything. I have no idea if my hypothesis is correct. I was just "thinking outside the box" and skewness popped into my head as something potentially interesting to look at.

If Shouright had the data, he could do one of his partial correlation calculations between winning percentage and mean YPC, controlling for skewness.




royalshank said:
I know you caveated the skewness measure but am curious if this formula is something commonly practiced. It's just interesting to see a "mean-median" calculation when one is used in parametric stats and the other in non-parametric stats. I'd be interested in any link to this use of the mean and median.

I'd also be interested if you guys have ever tried fitting any type of model to "winning/losing" outcome for the same data set that you are calculating the correlations from. Be interesting to see what a model "says" that gives you the optimal chance of winning. Good stuff here.
Click to expand...
 
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nyashfan said:
http:// http://en.m.wikipedia.org/wiki/Nonparametric_skew

I asked Shouright if there is a public database to download in order to do analyses and he didn't think there was. I think he gets pre-aggregated data from Football Outsiders and then does his own correlations.

The motivation behind using the (mean - median) / standard deviation definition of skewness is that its domain is from -1 to +1. It is thus interpretable in a similar manner to a correlation. See attached link.

I have never seen skewness used for anything. I have no idea if my hypothesis is correct. I was just "thinking outside the box" and skewness popped into my head as something potentially interesting to look at.

If Shouright had the data, he could do one of his partial correlation calculations between winning percentage and mean YPC, controlling for skewness.
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See what you think when you click on "Show All..." in the table entitled "Team Offense" at this link:

http://www.pro-football-reference.c...esult=&margin_min=&margin_max=&order_by=yards
 
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