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Five Downs With Football Outsiders: Do Cowboys or Eagles have better cornerback crew?
8:00 AM Fri, Sep 12, 2008 | Permalink | Yahoo! Buzz
Tim MacMahon http://www.***BANNED-URL***/blogs/images/email-icon.jpg E-mail http://www.***BANNED-URL***/blogs/images/email-icon.jpg News tips
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Bill Barnwell, a contributing editor at footballoutsiders.com and one of the minds behind the must-read Pro Football Prospectus, will answer five Cowboys questions each week of the season using the FO data and methodologies. Here's the Week 2 edition:
1. The Cowboys and Eagles both have elite cornerback trios. Which one is better according to your data?
It's going to be an unpopular answer, but I'm going to say it's about even. Last year, the Cowboys were 9th in the league in defensive pass DVOA, and the Eagles were 12th; very few people would argue that the Eagles' pass rush, though, matched up to the Cowboys. That, of course, was with Joselio Hansen as one of the Eagles' top three cornerbacks, not Asante Samuel.
If we look at the secondaries, they're actually pretty similar in make. Each team has the guy who got the big contract recently (Samuel and Terence Newman), the guy who saw his performance decline dramatically in 2007 (Lito Sheppard and, technically, Adam Jones), and the guy who always gets positioned as the afterthought, but ends up being an underrated performer (Sheldon Brown and Anthony Henry). Let's evaluate each pairing.
In New England, Samuel benefited from a very good pass rush, but there's no question that he was a very good cornerback. The average pass thrown at him gained 6.3 yards in 2007; that was 14th-best in the NFL. That doesn't sound great, but you have to remember that much of the safety help was pushed towards Ellis Hobbs on the other corner, as well into the box to assist the aging Patriots linebackers in pass support. Newman had a good year, especially after he got healthy, but he wasn't up to the same standard; he gave up 6.9 yards per attempt, 29th-best in the league. On the other hand, Newman spent more time on opposing team's top wide receivers than Samuel; he was on the opposing team's top receiving option 50%, tenth-most in the league. Samuel was only on the other team's top guy 43% of the time. I'd give the edge to Samuel, but only by a little bit.
In 2006, both Lito Sheppard and Adam Jones had very good years. Jones we spoke about last week; he allowed a league-best 5.4 yards per attempt, and passes against him were a successful play for the defense 63% of the time, second-best in the league. That's despite spending a good chunk of his time on No. 1 receivers; it was a fantastic performance worthy of any amount of hype you could provide him. Sheppard, to compare, allowed 6.0 yards per attempt (20th in the league) and had a success rate of 60% (ninth). While Sheppard benefits from actually playing last year, Jones is the more talented player.
Finally, we have Brown and Henry. Henry had better numbers last year, averaging 6.0 yards per attempt (11th) to Brown's 7.4 yards per attempt (41st). Brown, though, was often in single coverage and spent more time on the opposing team's top receiver than Henry did. I think most NFL observers would choose Brown over Henry, and I'd have to do the same -- that's enough to push the Eagles slightly over the top when it comes to analyzing corners.
2. There's a lot of talk about Donovan McNabb returning to his old form after he lit up the Rams. Should we believe that hype?
At Football Outsiders, we refer to Week 1 as "National Jump To Conclusions Week" for obvious reasons. People get really excited about a performance and extrapolate dramatic changes from it. Sometimes, that's the case, but it's often just an aberration. In Week 1 of the 2007 season, Josh McCown threw for 313 yards, and the Browns were blown out by the Steelers so badly that Cleveland beat writers were calling for Romeo Crennel's head. Things can change rapidly.
McNabb was up against one of the worst pass defenses in football, one that blew coverages on multiple plays (notably the long Hank Baskett touchdown). Every team blows coverages, but the Cowboys will be way more composed and have a much better pass rush to attack McNabb with. I don't doubt that McNabb will have a good year, but he's not going to be that guy from Week 1 every time out.
3. Who is the more effective back: Marion Barber or Brian Westbrook?
I mentioned a statistic earlier called Success Rate for cornerbacks; we have a similar statistic for running backs. What the running back metric does is track the percentage of the time a player helps his team progress towards or past the first-down marker. Although there are minor adjustments for time and score differential, in general, a successful play is one that gains 40 percent of the yards to go on first down, 60 percent of the yards to go on second down, or a full 100 percent of the yards to go on third or fourth down.
Last year, Barber's success rate was 49%; while that was far above Julius Jones' 37%, it was below Westbrook's success rate of 56%. To me, that makes Westbrook the more effective back without even considering his significant advantage in the passing game.
4. In the statistical measures considered most important for offensive lines, how did the Cowboys rank last season? After one game this season?
The metric we use to analyze offensive line play is a little complicated; it's a regression analysis we term "Adjusted Line Yards". You can find a detailed explanation at the bottom of this page, but I'll try and summate it into a paragraph.
To calculate Adjusted Line Yards, we look at the length of each carry and analyze its variability -- namely, how likely the back is to have gained the yardage "himself" as opposed to strictly through his offensive line. We calculate the likelihood that the team would get the yardage it did on that play with a different back based upon how other players do and the strength of the opposing defense. We then note all of that and regress it across all backs and plays to try and delineate the difference between the effectiveness of a running back and that of an offensive line. Finally, we adjust performance on a play-by-play basis for down, distance, situation, and opponent, and then normalize the statistics so that the average Adjusted Line Yards per carry on a play is exactly the same as the league average for standard yards per carry. It's certainly not a perfect formula, but it's definitely a step in the right direction.
Last year, the Cowboys ranked 14th in the league in Adjusted Line Yards. I suspect that, in reality, their run blocking is better than that. It certainly looked so in Week 1.
We also track performance in several other situations that doesn't use Adjusted Line Yards. We track the team's performance in "Power" runs, which we define as runs on third or fourth down with two or less yards to go, as well as first or second-and-goal runs from inside the two. In those scenarios, the Cowboys ran for a first down or a touchdown 68% of the time, good for 12th in the league.
They pulled off a lot of big runs, though; we have another stat we call "10+ Yards", which simply measures the number of rushing yards each team had when you ignore the first ten yards past the line of scrimmage on each play. The Cowboys ranked 11th in this statistic.
The most surprising metric we can talk about with the Cowboys, though, is the "Stuffed" stat. That tracks the percentage of runs that gain either zero or negative yards on first down, or less than 25% of the yards needed for another first down on subsequent downs. The Cowboys were "stuffed" 26% of the time, making them 24th in the league.
5. Is Brian Dawkins still a premier safety?
It's up for debate. Statistically, he was very effective last year. In coverage, he allowed only 3.4 yards per attempt towards him, good for third-best amongst safeties in the league, and a fifth-best success rate of 65%. Despite moving further into the box, though, his run numbers didn't improve; he allowed 6.8 yards per running play at him, pegging him 52nd amongst safeties in the league.
Watching him play, it's pretty clear that he's lost a step. What I noticed him do was cheat a lot in his tackles -- instead of taking on blockers head on, he was going around them more frequently, trying to compensate for a lack of speed by beating a ballcarrier to a spot. That keeps Dawkins healthier, but it also gives him worse angles on tackles, and Dawkins blew far more tackles last year than he ever has before.
8:00 AM Fri, Sep 12, 2008 | Permalink | Yahoo! Buzz
Tim MacMahon http://www.***BANNED-URL***/blogs/images/email-icon.jpg E-mail http://www.***BANNED-URL***/blogs/images/email-icon.jpg News tips
http://cowboysblog.***BANNED-URL***/NS_16TO-INT-thumb-250x247.jpg
Bill Barnwell, a contributing editor at footballoutsiders.com and one of the minds behind the must-read Pro Football Prospectus, will answer five Cowboys questions each week of the season using the FO data and methodologies. Here's the Week 2 edition:
1. The Cowboys and Eagles both have elite cornerback trios. Which one is better according to your data?
It's going to be an unpopular answer, but I'm going to say it's about even. Last year, the Cowboys were 9th in the league in defensive pass DVOA, and the Eagles were 12th; very few people would argue that the Eagles' pass rush, though, matched up to the Cowboys. That, of course, was with Joselio Hansen as one of the Eagles' top three cornerbacks, not Asante Samuel.
If we look at the secondaries, they're actually pretty similar in make. Each team has the guy who got the big contract recently (Samuel and Terence Newman), the guy who saw his performance decline dramatically in 2007 (Lito Sheppard and, technically, Adam Jones), and the guy who always gets positioned as the afterthought, but ends up being an underrated performer (Sheldon Brown and Anthony Henry). Let's evaluate each pairing.
In New England, Samuel benefited from a very good pass rush, but there's no question that he was a very good cornerback. The average pass thrown at him gained 6.3 yards in 2007; that was 14th-best in the NFL. That doesn't sound great, but you have to remember that much of the safety help was pushed towards Ellis Hobbs on the other corner, as well into the box to assist the aging Patriots linebackers in pass support. Newman had a good year, especially after he got healthy, but he wasn't up to the same standard; he gave up 6.9 yards per attempt, 29th-best in the league. On the other hand, Newman spent more time on opposing team's top wide receivers than Samuel; he was on the opposing team's top receiving option 50%, tenth-most in the league. Samuel was only on the other team's top guy 43% of the time. I'd give the edge to Samuel, but only by a little bit.
In 2006, both Lito Sheppard and Adam Jones had very good years. Jones we spoke about last week; he allowed a league-best 5.4 yards per attempt, and passes against him were a successful play for the defense 63% of the time, second-best in the league. That's despite spending a good chunk of his time on No. 1 receivers; it was a fantastic performance worthy of any amount of hype you could provide him. Sheppard, to compare, allowed 6.0 yards per attempt (20th in the league) and had a success rate of 60% (ninth). While Sheppard benefits from actually playing last year, Jones is the more talented player.
Finally, we have Brown and Henry. Henry had better numbers last year, averaging 6.0 yards per attempt (11th) to Brown's 7.4 yards per attempt (41st). Brown, though, was often in single coverage and spent more time on the opposing team's top receiver than Henry did. I think most NFL observers would choose Brown over Henry, and I'd have to do the same -- that's enough to push the Eagles slightly over the top when it comes to analyzing corners.
2. There's a lot of talk about Donovan McNabb returning to his old form after he lit up the Rams. Should we believe that hype?
At Football Outsiders, we refer to Week 1 as "National Jump To Conclusions Week" for obvious reasons. People get really excited about a performance and extrapolate dramatic changes from it. Sometimes, that's the case, but it's often just an aberration. In Week 1 of the 2007 season, Josh McCown threw for 313 yards, and the Browns were blown out by the Steelers so badly that Cleveland beat writers were calling for Romeo Crennel's head. Things can change rapidly.
McNabb was up against one of the worst pass defenses in football, one that blew coverages on multiple plays (notably the long Hank Baskett touchdown). Every team blows coverages, but the Cowboys will be way more composed and have a much better pass rush to attack McNabb with. I don't doubt that McNabb will have a good year, but he's not going to be that guy from Week 1 every time out.
3. Who is the more effective back: Marion Barber or Brian Westbrook?
I mentioned a statistic earlier called Success Rate for cornerbacks; we have a similar statistic for running backs. What the running back metric does is track the percentage of the time a player helps his team progress towards or past the first-down marker. Although there are minor adjustments for time and score differential, in general, a successful play is one that gains 40 percent of the yards to go on first down, 60 percent of the yards to go on second down, or a full 100 percent of the yards to go on third or fourth down.
Last year, Barber's success rate was 49%; while that was far above Julius Jones' 37%, it was below Westbrook's success rate of 56%. To me, that makes Westbrook the more effective back without even considering his significant advantage in the passing game.
4. In the statistical measures considered most important for offensive lines, how did the Cowboys rank last season? After one game this season?
The metric we use to analyze offensive line play is a little complicated; it's a regression analysis we term "Adjusted Line Yards". You can find a detailed explanation at the bottom of this page, but I'll try and summate it into a paragraph.
To calculate Adjusted Line Yards, we look at the length of each carry and analyze its variability -- namely, how likely the back is to have gained the yardage "himself" as opposed to strictly through his offensive line. We calculate the likelihood that the team would get the yardage it did on that play with a different back based upon how other players do and the strength of the opposing defense. We then note all of that and regress it across all backs and plays to try and delineate the difference between the effectiveness of a running back and that of an offensive line. Finally, we adjust performance on a play-by-play basis for down, distance, situation, and opponent, and then normalize the statistics so that the average Adjusted Line Yards per carry on a play is exactly the same as the league average for standard yards per carry. It's certainly not a perfect formula, but it's definitely a step in the right direction.
Last year, the Cowboys ranked 14th in the league in Adjusted Line Yards. I suspect that, in reality, their run blocking is better than that. It certainly looked so in Week 1.
We also track performance in several other situations that doesn't use Adjusted Line Yards. We track the team's performance in "Power" runs, which we define as runs on third or fourth down with two or less yards to go, as well as first or second-and-goal runs from inside the two. In those scenarios, the Cowboys ran for a first down or a touchdown 68% of the time, good for 12th in the league.
They pulled off a lot of big runs, though; we have another stat we call "10+ Yards", which simply measures the number of rushing yards each team had when you ignore the first ten yards past the line of scrimmage on each play. The Cowboys ranked 11th in this statistic.
The most surprising metric we can talk about with the Cowboys, though, is the "Stuffed" stat. That tracks the percentage of runs that gain either zero or negative yards on first down, or less than 25% of the yards needed for another first down on subsequent downs. The Cowboys were "stuffed" 26% of the time, making them 24th in the league.
5. Is Brian Dawkins still a premier safety?
It's up for debate. Statistically, he was very effective last year. In coverage, he allowed only 3.4 yards per attempt towards him, good for third-best amongst safeties in the league, and a fifth-best success rate of 65%. Despite moving further into the box, though, his run numbers didn't improve; he allowed 6.8 yards per running play at him, pegging him 52nd amongst safeties in the league.
Watching him play, it's pretty clear that he's lost a step. What I noticed him do was cheat a lot in his tackles -- instead of taking on blockers head on, he was going around them more frequently, trying to compensate for a lack of speed by beating a ballcarrier to a spot. That keeps Dawkins healthier, but it also gives him worse angles on tackles, and Dawkins blew far more tackles last year than he ever has before.
