Posted: 5:30 p.m. Wednesday, Sept. 25, 2013
By Tom Ryle
Facts. Data. Numbers.
If you think some of us here at Blogging The Boys get a little obsessed with them, I applaud your powers of observation. But there is some method to our madness. We are always searching for ways to measure the performance of the Dallas Cowboys and the teams they face.
I admit to being a relative newbie to the world of football statistical analysis. I have started using a lot of the numbers from Pro Football Focus lately. I find that the story the numbers tell me tend to agree with what I see when I watch the games. But one thing I have wished I could get that I have not found there is a way to judge the performance of units of the team. In particular, I am curious about how the offensive line is playing as a whole. When you look at things like pulling guards and the way two or three linemen have to pick up and hand off stunting and blitzing players, the numbers for one player don't always tell enough of the story. I have been wondering if there is some way to get a quantified evaluation of how the entire line does as a whole.
Well, a little German bird told me about another site that attempts to do just that. Advanced NFL Stats has some measurements that they use to determine the effectiveness of the offensive line as a unit. Here are two of the ones they consider the most meaningful:
Win Probability Added (WPA) - The difference between a team's Win Probability (WP) at the start of a play and the WP at the end of the play. WPA is the measure of a play's impact on the outcome of a game. An individual player's WPA is the sum of the WPA of the plays in which that player was directly involved. Being directly involved is defined as an offensive player who ran, threw, or kicked the ball, was targeted by a pass, or flagged for a penalty. Defensive players are credited for WPA when they tackle or sack the ball carrier, are credited with an assisted tackle or sack, cause a fumble, defend a pass, or are flagged for a penalty.
Expected Points Added (EPA) - The difference between the Expected Points (EP) at the start of a play and the EP at the end of they play. EPA is the measure of a play's impact on the score of the game. An individual player's EPA is the sum of the EPA of the plays in which that player was directly involved. Being directly involved is defined as an offensive player who ran, threw, or kicked the ball, was targeted by a pass, or flagged for a penalty.
One thing you might notice is the definition of "directly involved". Despite the way it is presented here, they also determine these numbers for the offensive line, but not for the individual linemen. If you want to get further definitions of the terms, like WP and EP, you can check the full glossary.
So, how is the Dallas O-line faring by these numbers? We know that PFF has Doug Free as the top tackle, and Tyron Smith is doing well, but the interior of the line is more middle of the road in their analysis - at best. Travis Frederick sometimes looks like the rookie he is, and the team is still experimenting with Ronald Leary, Mackenzy Bernadeau, and Brian Waters to figure out who the best two guards are. But when you look at the overall performance of the line, the Advanced NFL Stats number for EPA, or how much they impact the score, is 17.1. And when compared to all the teams in the NFL, that ranks them . . .
First. As in number one. The best. Top o' the heap.
Bet you didn't see that one coming. Well, unless you figured I was not going to go into introducing a new metric into my repertoire if I didn't like the outcome. In my defense, I will say that this is not a week to be looking for explanations of things that went wrong. I am trying to figure out if the marked success of the victory over the St. Louis Rams is a fluke or a trend. And this does offer some encouragement that we may see more of this.
Of course, while scoring is related to winning, not all teams win the same way. The performance of the defense will have an indirect effect, for one thing. The rankings under WPA are not identical to EPA. The WPA score for the Cowboys is 0.61. Which is . . .
First again. OK. You probably had an inkling about this one. If you want to see the full charts, you can click here. The columns are sortable. The site also has analysis of all the other parts of the team, so you can see where the Cowboys are not doing so well. Tony Romo, for instance, is down close to the median for quarterbacks so far this season. DeMarco Murray is tied for eighth under WPA, but seventeenth under EPA, which seems to make sense to me. He's helped the team win, but only scored one touchdown.
I will not pretend to know the mathematics behind these numbers, but like PFF and Football Outsiders, ANS is very serious about finding numbers that conform to real world results. In other words, they work very hard at making sure that the figures relate closely to actual win-loss records.
The main reason I wanted to write this up was that it confirms something I, and possibly many of you, think we are seeing. The offensive line is doing much better this year, particularly in protecting Romo. That's what the eyeball test has been coming up with when I watch the games, and now there is some numerical analysis that comes to the same conclusion.
And how many times has someone here at BTB said that this team will go as far as the offensive line can go? Well, if these numbers are accurate, and more importantly, if they hold up for the rest of the season, this is extremely good news. It means that the Cowboys finally have the line they need to let Bill Callahan exploit the offensive arsenal. Add in the fact that this line is still to an extent a work in progress, and good things may be in the future.
No matter how you may feel about all this statistical analysis, I think you can agree that this is a very solid indication that the Dallas O-line does not suck this year. And if that doesn't bring a smile to your face, then thanks for visiting and don't troll in the comments.