Last week, a reader suggested we perform a value-based statistical analysis (similar to our 2009 Player Grades ) which could be used to determine the worth of one player over another. For example, how much better would the Cowboys be if Felix Jones played every snap at running back (disregarding fatigue)? How costly would an injury to Jason Witten be? Essentially, how much does each player contribute to a win?
This task is easier said than done (and since it isn’t even particularly easily said, it sure isn’t easy to do). As the reader points out, one would have to “normalize” the conditions outside of the player to determine his true worth. This is rather easy to do (relatively speaking) in a sport like baseball where the circumstances are basically always the same.
In football, though, no two plays are ever really identical. Statistical comparisons among players on different teams are rather pointless, as the nature of each player’s system plays an incredible role in his statistical capabilities.
Nonetheless, there have been some attempts to “normalize” outside factors and assign an objective value to players. In fact, we are in the process of making such an attempt right now. Until then, we wanted to take a look at the values of Cowboys players gathered by some other leading football statistics gurus (and compare them to our own 2009 Player Rankings ).
One such source (and perhaps the most well-known) is Football Outsiders . The primary FO statistic with which we are concerned is DVOA, or Defense-adjusted Value Over Average. FO describes DVOA as “representing value, per play, over an average player at the same position in the same game situations.”
DVOA is an excellent statistic to use to compare with our own player rankings, as both represent efficiency , not overall value . For example, Roy Williams had a greater overall value to the offense than Kevin Ogletree in 2009, but most would argue Ogletree was more efficient during his snaps.
Another source of efficiency-based value rankings is Advanced NFL Stats —a site we refer you to a lot. Advanced NFL Stats implements a statistic called Expected Points Added. We’ve spoken about "expected points" in the past, and ANS talks about it here .
In short, EP (expected points) is the value of a certain situation in football. EPA (expected points added) is the difference between one situation and another. If the Cowboys have a 1st and 10 at their own 30-yard line, for example, the EP of that situation is +1.0 point, i.e. on average, they can expect one point from that drive. If Miles Austin catches a pass for 50 yards, the Cowboys’ EP shoots up to +4.0 (the expected points of a 1st and 10 at the opponent’s 20-yard line). Thus, the EPA for that play is +3.0.
We are concerned with EPA/play—the amount of expected points a player adds to his team’s point total per play.
A final source for efficiency-based values is Pro Football Focus . PFF is different from FO and ANS in that they do not necessary use the outcomes of plays to formulate rankings. Instead, they break down each play and assign values based on their interpretation of how well each player performed his job on that play. You can read more about their methodology here .
It is important to note that all three sites use a value of “0″ as a baseline for average play. Players in the negative are worse than average, and players with positive values are better than average for DVOA, EPA, and PFF’s values.
The chart above displays the rankings and values for the Cowboys offense from all three sites (Football Outsiders, Advanced NFL Stats, and Pro Football Focus), along with our own grades. A few notes before we analyze the data:
- NR=Not Rated (likely due to insufficient sample size)
- The statistics circled in blue are a player’s highest rating; those in red are his lowest.
- Comparisons among players at different positions are meaningless due to the nature of the data.
- Only two players, Martellus Bennett and Flozell Adams, were unanimously voted as “below average.”
- Tony Romo’s highest rating (from FO) put him at just seventh among all quarterbacks. PFF had him all the way at 15th.
We had Romo rated as the seventh-best quarterback in the NFL in our 2010 Starting Quarterback Power Rankings . We would have ranked his 2009 play, though, as top-five.
- It’s unanimous: Felix Jones is one of the NFL’s most efficient running backs. He was ranked fifth, sixth, and ninth, respectively.
Jones’ lowest grade would actually probably come from us. He has a long way to go to prove he can hold up over an entire season, but as far as efficiency, he’s one of the league’s best. We provided him a B+ in short-yardage running, an A in overall running, a B in receiving, and a B in pass protection .
- Two out our three sources agree with us that Barber was about average last season. FO ranked him as a top-15 back. Meanwhile, Tashard Choice checked in with a higher efficiency rating than Jones from two of the sites.
We rated Barber as an average running back in 2009 (77.2 percent). We were also very high on Choice, rating him just 2.5 percentage points behind Jones. Choice would have ranked as one of the league’s top running backs on Football Outsiders and Advanced NFL Stats had he played more snaps.
- Jason Witten was ranked all the way from the league’s top tight end to No. 11.
Witten was the No. 1 tight end in our NFL Tight End Rankings . There’s simply no doubt about it.
- Opinions on Deon Anderson varied from slightly below average to the league’s sixth-best fullback.
We tend to agree with the latter. The Cowboys averaged nearly two yards more per rush with Anderson in the game (as compared to John Phillips) and .2 yards more per pass. Click here to see our in-depth study on Anderson’s 2009 play.
- Miles Austin has arrived. He was rated from fifth to ninth.
We gave Austin the third-highest grade of any Cowboy due to his low 2.2 percent drop rate and incredible 10.4 yards-per-attempt.
- Ratings of both Patrick Crayton and Roy Williams varied.
Two of the three sources had Crayton as a top-16 receiver (in terms of efficiency). Williams wasn’t high on anyone’s list, but PFF had him ranked all the way down at No. 100.
- PFF was the only site to rank individual linemen, but their ratings fell in line with ours.
We were a bit higher on Leonard Davis and Andre Gurode and slightly lower on Kyle Kosier (who they listed as the Cowboys’ top lineman last season). We gave Davis and Gurode “A-” grades and Kosier a “B.” All three linemen made our list of Dallas’ top 15 overall players last season.
There is obviously quite a bit of work left to be completed in the area of advanced football statistics, particularly objective efficiency rankings. Still, the difficulty of the task is no reason to concede. The more we learn which statistics contribute to a team’s success (and how much), the closer we will be to “normalizing” subjective factors in an attempt to acquire objective player ratings.