Similar to my efforts to devise a better QB rating, I've applied the same method to estimating the wins contributed by running backs. Although not perfect, it provides a sense of who is helping his team and who is hurting his team, and by how much.
The components of the RB rating are weighted according to how important they are in terms of team wins. The formula is based on a multivariate regression model of team wins. Using data from the past five NFL regular seasons, the regression model estimates team wins based on the efficiency stats of each team including passing, running, turnovers, and penalties.
The rating includes Yards Per Carry (YPC), fumble rate, and an adjusted Yards After Catch per reception (YAC/Att). YAC/Rec is adjusted to reflect the fact that RB receptions constitute 14% of all team pass attempts. Fumble rate is defined as fumbles per carry plus receptions.
Some may ask why I don't include touchdowns in the rating. Touchdowns are the result of yards per carry, reception yds, etc. Including TDs would also skew the rating towards the Alstott-esque "vulture-backs." Also, rushing TDs are often the result of an excellent passing game that frequently gets the ball close to the goal line, and not necessarily the result of good rushing.
The RB rating is computed in terms of how many wins a RB contributes to his team through his level of performance over the course of a full 16-game season, all other things being equal. The equation is:
+WP16 = [(YPC * 0.92) + (YAC/Att * 1.57) - (Fum Rate * 63.2)] - 4.0
(I subtract 4.0 as the linear constant because it's the average score for RBs. An average RB on an average team would produce exactly 8 wins, not 12.)
The resulting ranking of 2006 RBs is below. Keep in mind the list assumes a full 16-game season for each RB.
Player | Team | Rush | YPC | YAC/Att | Fum | +WP16 |
Norwood | ATL | 99 | 6.4 | 0.5 | 0 | 2.6 |
Jones-Drew | JAC | 166 | 5.7 | 0.6 | 1 | 1.8 |
Tomlinson | SDG | 348 | 5.2 | 0.6 | 2 | 1.3 |
Jones | DAL | 267 | 4.1 | 1.0 | 1 | 1.1 |
Barber III | DAL | 135 | 4.8 | 0.4 | 0 | 1.1 |
Westbrook | PHI | 240 | 5.1 | 0.5 | 2 | 1.0 |
Barber | NYG | 327 | 5.1 | 0.5 | 3 | 1.0 |
Taylor | JAC | 231 | 5 | 0.7 | 3 | 0.9 |
Portis | WAS | 127 | 4.1 | 0.7 | 0 | 0.8 |
Johnson | KAN | 416 | 4.3 | 0.7 | 2 | 0.7 |
Gore | SFO | 312 | 5.4 | 0.5 | 6 | 0.6 |
Addai | IND | 226 | 4.8 | 0.5 | 2 | 0.6 |
Benson | CHI | 157 | 4.1 | 0.6 | 0 | 0.6 |
Maroney | NWE | 175 | 4.3 | 0.6 | 1 | 0.6 |
Bell | DEN | 157 | 4.3 | 0.6 | 1 | 0.5 |
Jacobs | NYG | 96 | 4.4 | 0.9 | 2 | 0.3 |
Williams | CAR | 121 | 4.1 | 0.6 | 1 | 0.3 |
Dillon | NWE | 199 | 4.1 | 0.7 | 2 | 0.3 |
Jackson | STL | 346 | 4.4 | 0.5 | 4 | 0.3 |
Jones | CHI | 296 | 4.1 | 0.4 | 1 | 0.2 |
Washington | NYJ | 151 | 4.3 | 0.6 | 2 | 0.2 |
Dunn | ATL | 286 | 4 | 0.5 | 1 | 0.2 |
Henry | TEN | 270 | 4.5 | 0.4 | 3 | 0.0 |
Dayne | HOU | 151 | 4.1 | 0.4 | 1 | 0.0 |
Jordan | OAK | 114 | 3.8 | 0.6 | 1 | -0.1 |
McAllister | NOR | 244 | 4.3 | 0.4 | 3 | -0.1 |
Lundy | HOU | 124 | 3.8 | 0.5 | 1 | -0.1 |
Betts | WAS | 245 | 4.7 | 0.5 | 6 | -0.1 |
Houston | NYJ | 113 | 3.3 | 0.5 | 0 | -0.3 |
Morency | GNB | 96 | 4.5 | 0.5 | 2 | -0.3 |
Green | GNB | 266 | 4 | 0.6 | 4 | -0.3 |
Fargas | OAK | 178 | 3.7 | 0.4 | 1 | -0.3 |
Brown | MIA | 241 | 4.2 | 0.5 | 4 | -0.3 |
McGahee | BUF | 259 | 3.8 | 0.7 | 4 | -0.3 |
Parker | PIT | 337 | 4.4 | 0.5 | 7 | -0.4 |
Bush | NOR | 155 | 3.6 | 0.5 | 2 | -0.5 |
Morris | SEA | 161 | 3.8 | 0.3 | 1 | -0.5 |
Taylor | MIN | 303 | 4 | 0.4 | 5 | -0.6 |
Bell | DEN | 233 | 4.4 | 0.4 | 5 | -0.6 |
Thomas | BUF | 107 | 3.5 | 0.4 | 1 | -0.7 |
Lewis | BAL | 314 | 3.6 | 0.5 | 4 | -0.8 |
Foster | CAR | 227 | 4 | 0.3 | 4 | -0.8 |
Williams | TAM | 225 | 3.5 | 0.4 | 3 | -0.9 |
Jones | DET | 181 | 3.8 | 0.6 | 5 | -0.9 |
James | ARI | 337 | 3.4 | 0.3 | 3 | -0.9 |
Rhodes | IND | 187 | 3.4 | 0.4 | 3 | -1.1 |
Johnson | CIN | 341 | 3.8 | 0.3 | 6 | -1.1 |
Droughns | CLE | 220 | 3.4 | 0.5 | 5 | -1.4 |
Barlow | NYJ | 131 | 2.8 | 0.3 | 1 | -1.5 |
Alexander | SEA | 252 | 3.6 | 0.3 | 6 | -1.7 |
YAC/Rec is adjusted to reflect the fact that RB receptions constitute 6% of all team pass attempts.
2006=15%
2005=14%
where did you get 6 per cent?
also, have you considered first downs per attempt?
Good catch. How did you do that so fast? I just posted this. It should say 14% and I've corrected it. The math in the table was correct thankfully, just not my write up.
Personally, I'm a believer in not including result-oriented stats such as 1st downs or touchdowns. I realize there is a valid reason to include them. For example, a RB who grinds out 2.5 yds on a 3rd and 2 should be rewarded and not penalized. But for now at least, I prefer to keep things as simple as possible.
But on the other hand, why credit a RB who runs for a 1st down on 2nd and 2 following an 8-yd pass on 1st down?
The goal line dives and similar plays average out to a substantial degree, so I think there is more to gain than lose by excluding 1st downs and touchdowns.
there was a really good downloadable database from statsworld called football stats.
It had all the basic stats plus stuffs and passes defensed for teams, players, and sorted by position. Also it has individual first downs.
so i was able to quickly put total pass attempts into a spreadsheet, then get the total passes caught by rb's and divide. Very fast.
Now they only have an online version which costs more money but you should check it out.
I'd prefer to see this list with the numbers adjusted for how many attempts the RB has. Jerious Norwood and MJD probably weren't the backs who most contributed to their team success last year, because they didn't have 200+ attempts, and if they did have 350 attempts like true workhorse backs, they likely wouldn't have been so efficient.
Essentially, extrapolating Norwood or MJD's stats to a much larger number of attempts just ends up letting them benefit from small sample size.
Alan-There is definite value in what you suggest, and I may just post such a ranking. But I'm trying to zero in on player skill, which is largely independent of attempts.
For example, NE RBs will benefit disproportionately from lots of clock-grinding 4th quarter carries and yards because NE's potent passing game gives the Pats a big lead.
Norwood had 99 attempts, whch is anything but a small sample size. I think that MJD's and Norwood's stats are inflated somewhat, but because they were primarily 3rd-down backs whose carries were sometimes draw plays on 3rd and long. Norwood also had the benefit of Vick who caused many defenses to cover the edges. They also weren't the short-yardage/goal line backs for whom a successful run might only yield 1 or 2 yds.
cbm-Thanks for the tip on statsworld.
It's interesting that your ratings back up the recent popular assumption that runningbacks just aren't that important. Compared to the QB list, RBs are bunched very closely.