Over the years, we've frequently used a metric called Approximate Value, a metric courtesy of Pro-Football-Reference.com, here on Blogging The Boys. If you're a regular reader, you're probably familiar with the metric, if not, or if you're new to our little corner of the interwebs, consider this post your introduction.
Approximate Value (AV) and the closely related Career Approximate Value (CAV) is something we've repeatedly used over the last six years, particularly during draft coverage. And as we get into the swing of all things draft related over the coming weeks and months, we'll probably use the once again. 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.
There is a difference between seasonal AV stats and the Career AV stats at pro-football-reference.com. While AV shows the Approximate Value for a single season, Career AV computes a weighted sum of the seasonal AV scores: 100% of the player's best season, plus 95% of his 2nd-best season, plus 90% of his 3rd-best season, plus 85% of his 4th-best season, and so on.
There are many ways to use the AV or CarAV metric, and today we'll use it to take a high-level view of the 2015 Cowboys roster. But before diving into the numbers, some more explanation from PFR:
"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 21 points, followed by Aaron Donald and Cam Newton (both 20), and Andrew Whitworth and Russell Wilson (both 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 2015|
|19-21||MVP- or Player Of The Year level performance||5|
|12-18||All-Pro/Pro Bowl level performance||52|
|3-5||Backup player or limited playing time||439|
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 10 points to zero.
Eight to 10 points - The Cowboys All Pros
The AV metric is heavily weighted toward rate- or counting stats like passing yards or rushing yards, so it's no surprise that not many Cowboys graded out in double digits this year. Smith, Frederick, and Martin top the list of Cowboys largely due to their post-season honors.
Seven Points - The Wiley Veterans
1. Sean Lee
2. Darren McFadden
3. Nick Hayden
If not for the fact that the universe is cruel and unjust, Sean Lee would have made the Pro Bowl and would be ranked higher here. Regardless, Lee may have had the best season of his career, unfortunately that season was with one of the lesser defenses in the league. Darren McFadden did have a career year with 1,089 rushing yards, but didn't help the Cowboys get more than four wins.
Hayden is a bit of a surprise here, but the AV metric seems to like what the Cowboys defensive tackles did overall, and it awards Hayden for getting 15 starts
Seven Points - The Future Franchise Cornerstones
Here's what the AV metric sees: both Crawford and Lawrence made their share of plays, even if Lawrence's plays were more spectacular, and both played 16 games, with Crawford getting 16 starts and Lawrence 13. That's more than any other members of the defensive line not named Nick Hayden.
And that has to count for something.
Six Points - The Veteran Starters
5. J.J. Wilcox
If your first thought is, "why are these players ranked so high?", don't worry, they're not. 6 points in AV terms is still starter quality, but barely. These are players that notched the prerequisite number of starts, but didn't show up much on the stat sheet with sacks or interceptions. Greg Hardy and Rolando McClain did fill up the stat sheet, but came up a little short with 12 and 11 starts respectively.
AV is not as precise a metric as other metrics (e.g. PFF grades) and doesn't differentiate much between players in the same position group. The AV for for a player is determined in part by the overall play of his position group, and when a single player doesn't do anything to stand out from his position group, he'll likely get the the same AV as the total position group. AV says that that the defensive backs are an average starting group, and since neither Church, Carr, or Wilcox did much to stand out from the group, they all get the same AV - and their number of starts rate them as starters.
Backups: The Borderline Starters
Five Points - The Senator
1. Jason Witten
Witten didn't have a particularly outstanding year on the stat sheet, and AV doesn't account for the blocking work of a tight end. But calling him a borderline starter isn't doing him any justice, so he gets his own Senator category.
Five Points - The Young Guns
1. Terrance Williams
2. Anthony Hitchens
There really isn't much of a difference between Williams and Hitchens and the six-point players, except that their number of starts (13 and 9 respectively) are a bit lower than you'd want for a starter.
Bailey may look like a mistake here, he made the Pro Bowl and is an All Pro after all, but that's just how AV handles kickers. Worry not: Bailey has the second-highest AV of all kickers in the league.
Four points - The Backups
These are players who either missed significant time with injury (Claiborne) or were late getting starting roles (Collins & Jones).
Three Points - Situational Players
3. Dez Bryant
Beasley and Wilber only saw action in limited, and specialized roles, Beasley as the slot guy and Wilber as the strongside linebacker. Bryant's lack of stats and lack of playing time (just 9 starts) put him in this category for 2015, though that's not where he belongs when healthy, obviously.
Two Points - The Marginal Contributors:
1. Tony Romo
2. Kellen Moore
5. Lance Dunbar
6. Jeff Heath
7. Jack Crawford
8. Chris Jones
These are all players who received limited playing time for different reasons (plus the punter). Notice how Romo 4 starts), Weeden (3 starts) and Moore (2 starts) are all ranked above Matt Cassel (7 starts), who we find in the next group:
One Point - The Role Players:
1. Matt Cassel
4. Andrew Gachkar
6. James Hanna
8. L.P. Ladouceur
9. Ronald Leary
10. Danny McCray
11. Terrance Mitchell
12. Ayodeji Olatoye
14. Devin Street
15. Robert Turbin
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.
The question here is all about trajectories. Which of these players are pointing up and which are pointing down (some have already been released).
Zero Points - The Scrubs:
This list contains all players who were active on the game-day roster at least once in 2015 (and are not on IR) but did not record any significant stats or playing time.
1. Gavin Escobar (236 snaps)
2. Tyler Clutts (133)
3. Casey Walker (57)
4. Terrell McClain (45)
5. Davon Coleman (44)
8. Christine Michael (25)
12. (- -)
13. (- -)
14. Josh Thomas (- -)
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 2015, and most of these players did not accumulate any significant playing time as you can see by the snap count (offense or defense) behind each name.
In total, that's 177 AV points for the Cowboys, which ranks them in the bottom five of the league. That's what happens when you finish 31st in points scored and 29th in scoring differential.
Keep in mind that injuries/suspensions played a role in these numbers and in the overall state of the team, so while it would be easy to say the 177 AV points mean the Cowboys simply didn't have enough good players, it's probably more accurate to say that the Cowboys simply didn't have enough healthy players, especially at some of the critical roster spots.
Of course, this is just one more way of looking at the roster. But it does provide an alternative angle from which to evaluate the 2015 performance.