If you're a regular reader of Blogging The Boys, you're probably familiar with a metric called Approximate Value. If not, consider this post your introduction.
We've used Approximate Value (AV) and the closely related Career Approximate Value (CAV) on and off for the last five years or so, and particularly often during our draft coverage. As we ramp up our draft coverage again this year, we'll likely feature the metric repeatedly. So in order to get everybody on the same page, we'll use this post as a detailed introduction to AV.
"Approximate Value" was developed by Doug Drinen at Pro-Football-Reference.com and is designed to assign a specific value to any player at any position for any given year. The algorithm behind AV weights position specific metrics (i.e. yards or points scored/allowed) with an indicator for durability (total games played and seasons as their team's primary starter) and quality (Pro Bowl and All Pro nominations) and then normalizes all this at a team level. Drinen left PFR a while back, but PFR continue to update these number, most recently on Wednesday this week.
There are many ways to use the AV metric, one of them is to look at the 2014 Cowboys roster through the AV lens, which is what we'll do today. Before diving into the Cowboys' numbers though, a little more explanation by Doug Drinen:
"Essentially, AV is a substitute for --- and a significant improvement upon, in my opinion --- metrics like 'number of seasons as a starter' or 'number of times making the Pro Bowl' or the like. You should think of it as being essentially like those two metrics, but with interpolation in between."
And like every stat, AV has its limitations.
"AV is not meant to be a be-all end-all metric. Football stat lines just do not come close to capturing all the contributions of a player the way they do in baseball and basketball. If one player is a 16 and another is a 14, we can't be very confident that the 16AV player actually had a better season than the 14AV player. But I am pretty confident that the collection of all players with 16AV played better, as an entire group, than the collection of all players with 14AV."
This is an important aspect to keep in mind: The AV numbers are relative. Players on good teams will score higher than players on bad teams, some positions (e.g. QB) will score higher than others (e.g. safeties), position groups (e.g. offensive linemen) will score roughly the same even if there are differences in actual performance.
The AV number starts at 0 and has gone as high as 26 only once in the Super Bowl era: In 2006 Ladanian Tomlinson reached that mark when he set the NFL record for rushing TDs (28) and also topped the league with 1,815 rushing yards.
Topping this year's list is J.J. Watt with 24 points, followed by Aaron Rodgers (21), DeMarco Murray (19) and Russell Wilson (19). AV points are fluid from one year to the next, but a rough scale for this year would look something like this:
|AV||Description||No. of players 2014|
|19-25||MVP- or Player Of The Year level performance||4|
|12-18||All-Pro/Pro Bowl level performance||56|
|3-5||Backup player or limited playing time||436|
Note that there are only 478 players in the league with an AV of 6 points or more, an indication of starter quality. That's an average of only about 15 players per NFL team, and that's an important take-away here: No team in the league has starter quality at every position, especially not in the salary cap era. Keep that in mind as we review the Cowboys roster below, sorted in descending order from 19 points to zero.
Nineteen Points - The MVP
1. DeMarco Murray
The next best running backs are Le'Veon Bell (17), Eddie Lacy (16), and Marshawn Lynch (13). Do you think anybody in Pittsburgh, Green Bay, or Seattle is thinking, "Hey, let's let this guy walk, we can replace him with a running back by committee?" Probably not, but that seems to be a position held by a sizeable portion of Cowboys fans.
Twelve to Fifteen Points - The All-Pros
Tony Romo led the league with a 113.2 passer rating, but since the AV metric is heavily weighted toward rate- or counting stats like passing yards instead of efficiency metrics, Romo doesn't do too well in this metric. Romo is ranked eighth among all QBs, due in part to the fact that he only ranked 14th overall with 3,705 passing yards.
Dez Bryant is ranked fifth overall among wide receivers, because despite leading the league with 16 TDs, he "only" ranked eighth in total receiving yards.
The AV metric obviously likes the play of the Cowboys. Because of the way the metric is calculated, there isn't as much differentiation between linemen as you would get from Pro Football Focus for example. Smith, Martin, and Frederick rank above the remaining linemen on the strength of their post-season accolades.
Of note, Zack Martin is the highest-ranked rookie in the league with 14 points.
Eight Points - The Wiley Veterans
Jason Witten made the Pro Bowl for the 10th time this year, but his AV number is impacted by his (relative) lack of receiving yards. Jeremy Mincey in turn profits from a 6-sack season and the fact that he started every single game for the Cowboys.
Seven Points - The Future Franchise Cornerstones
These are three players that have received their share of criticism (especially from PFF's season grades), but here's what the AV metric sees: All three made their share of plays (in Leary's case as part of a very strong O-line), and were good enough to start 16 games (Williams, Wilcox) or 15 games (Leary) for a 12-4 team that shared the best W/L record in the league with a handful of other teams.
And that has to count for something.
Six Points - The Young Guns
2. Anthony Hitchens
There really isn't much of a difference between Crawford and Hitchens and the seven-point players, except that Crawford didn't notch a lot of stats (just 3 sacks) and Hitchens only started in 11 games.
Six Points - The Veteran Starters
Players like Church, Carr, Selvie and Hayden notched the prerequisite number of starts, but didn't show up much on the stat sheet with sacks or interceptions. Bruce Carter and Rolando McClain did but came up short with eight and 12 starts respectively.
The AV for linemen on both sides of the ball is determined in part by the overall performance of their unit. The stellar play of the O-line therefore rewards the slightly weaker players in the group, which the less spectacular performance of the D-line has negative on all defensive linemen.
Also, in contrast to a grading service like PFF, AV rewards one specific trait among NFL players, and that's the ability to stay healthy. Nick Hayden, PFF's favorite whipping boy, played and started in every single game, George Selvie started 13 games. In the AV metric, that's a positive even if you're playing as part of a subpar unit.
Backups: The Borderline Starters
Five Points: The Injured/suspended Starters
Both players would have rated higher had they not been injured or suspended. If you were to combine Free's AV (5) with Parnell's (3) you get a right tackle worth 8 AV points, which would rank that hypothetical right tackle up there with Witten and Mincey.
Three & Four points: The Backups
These are players who either missed significant time with injury (Durant, Melton) or backups who received playing as they spelled the starters or had specific but limited roles on the team.
Two Points - The Marginal Contributors:
1. Anthony Spencer
These are all players who received limited playing time for different reasons. The question in this group is about trajectories: Are their arrows pointing up or down?
One Point - The Role Players:
2. C.J. Spillman
12. Terrell McClain
13. Tyler Patmon
This is a bit of a tricky group. In principle, these are players who saw limited playing time, but for different reasons. Some of them are special teams aces, some were limited by injuries, some simply didn't put up a lot of production, some of them simply are career backups.
For the Cowboys, it's a little disappointing to see a lot of their recent draft investments (the equivalent of 1st-round pick, three 2nd-round picks, one 3rd-round pick) on this list. Morris Claiborne, DeMarcus Lawrence, and Gavin Escobar - for different reasons - have not been able to live up to their draft pedigree.
Zero Points - The Scrubs:
This list contains all players who were active on the game-day roster at least once in 2013 (and are not on IR) but did not record any significant stats or playing time. Note that special teams play is not included here or any of the metrics above.
2. Devin Street (150)
8. Tony Hills (5)
Before anybody starts hyperventilating about who the AV metric is calling a scrub, keep in mind that this is a measure of the performance in 2014, and most of these players did not accumulate any significant playing time as you can see by the snap count behind each name.
So there you have it, the entire 2014 Cowboys roster at a glance. In total (and including specialists), that's 233 AV points for the Cowboys, the sixth best value in the league behind the Seahawks (248), Packers (248), Patriots (243), Broncos (243), and Ravens (235).
Also, note that the Cowboys have 19 players with an AV of six points or more, tied for the most in the league. You may disagree with this, of course, but the AV metric says the Cowboys 19 of the 22 starting spots are manned by starter-quality players for the Cowboys (Sure, you'd like a Pro Bowl caliber player at every spot, but that simply isn't happening.) The three spots without a starter-quality player: corner, right tackle and the 11th guy on offense (either a receiver or a tight end).
Keep in mind that injuries/suspensions played a role in these numbers: A healthy Doug Free would have likely received about 8 AV points, and Orlando Scandrick would likely have received at least as many points as Brandon Carr.
Taken to its logical conclusion, if the Cowboys wanted to address the remaining roster hole, they'd have to draft a wide receiver or - wait for it - a tight end. Which just goes to show that relying too heavily on just one source of data may not lead to the best results.
If you want to check out the AV numbers in more detail, you can find the numbers on the team page of Pro Football Reference.