Can Elusiveness Be Measured?

Pro Football Focus has a new stat they've created that they've called Elusiveness. It's always been tough to measure how much of a running back's success is due to his offensive line and how much to his own innate abilities. Football Outsiders uses DYAR (Defense-adjusted Yards Above Replacement) which is a way of measuring how good a running back is compared to his replacement. DYAR explained. They also use DVOA (Defense-adjusted Value Over Average), and EY (Effective Yards). All of these stats attempt to measure how effective a running back is.

Here is how Football Outsiders explains Effective Yards:

Effective Yards, listed in red, translate DVOA into a yards per attempt figure. This provides an easy comparison: in general, players with more Effective Yards than standard yards played better than standard stats would otherwise indicate, while players with fewer Effective Yards than standard yards played worse than standard stats would otherwise indicate. Effective Yards are not the best way to measure total value because they are more dependent on usage than DYAR.

 

What I want to do is compare Pro Football's new stat with Football Outsiders rankings and then compare that with the NFL's more normal stat-keeping to see how much difference there is between the three. Join me after the jump for some fun stat-crunching. 

Elusiveness (as defined by PFF) is combined of three important statistics. The first is the number of yards after initial contact, the second is the ratio of missed tackles (whether after the catch or after the run). Here are some rankings and then the formula.

Top 10, percentage of yards after contact

Name Team Att. Yds. YCo YCo% YCo/Att.
Brian Leonard CIN 27 84 69 82.14 2.6
Chris Brown HOU 79 267 207 77.53 2.6
Larry Johnson KC 132 380 294 77.37 2.2
Marshawn Lynch BUF 120 450 339 77.37 2.2
Jason Snelling ATL 134 571 422 73.91 2.8
Mewelde Moore PIT 35 118 86 72.88 2.5
Michael Bush OAK 123 591 423 71.57 3.4
Tim Hightower ARI 143 597 426 71.36 2.9
Clinton Portis WAS 124 502 357 71.12 2.9

 

Bottom five, percentage of yards after contact

Name Team Att. Yds. YCo YCo% YCo/Att.
Tashard Choice DAL 64 349 124 35.53 1.9
Reggie Bush NO 70 396 146 36.87 2.1
Brian Westbrook PHI 61 274 126 45.99 2.1
Correll Buckhalter DEN 120 642 314 48.91 2.6
Thomas Jones NYJ 332 1,402 701 50.00 2.1

 

Rather interesting to see Thomas Jones' name at the bottom of the list--gives a whole new level of insight into why the Jets let him go. 

 

Top 10, missed tackles/reception ratio

Player Team Rec. Rec.MT MT/Rec. rating
Beanie Wells ARI 12 5 50.00
Jamal Lewis CLE 8 3 50.00
Pierre Thomas NO 39 16 43.59
Ahmad Bradshaw NYG 21 8 42.86
Tashard Choice DAL 15 5 40.00
Mewelde Moore PIT 21 7 38.10
Correll Buckhalter DEN 31 10 35.48
Fred Jackson BUF 46 15 34.78
DeAngelo Williams CAR 29 9 34.48
Ray Rice BAL 78 25 33.33

There are some interesting names there--it's surprising to me to see Beanie Wells so high on the list. One thing I can glean from this is that some of these running backs had poor offensive lines which is why the may have struggled in 2009. 

The formula devised by PFF is this: (MTrush+MTrec)/(Rec+Att)*(YCo/Att*100)

Here are the rankings. We have one 49er making the list and not in a good way.

 

Top 10, Elusive Rating

Name Team Att. Yds. YCo YCo/Att. MT Rec. Rec. MT Elusive
Rating
Justin Forsett SEA 114 623 363 3.2 23 41 11 70.19
Johnathan Stewart CAR 221 1,133 740 3.3 44 18 5 67.66
Pierre Thomas NO 147 793 445 3 19 39 16 56.45
Fred Jackson BUF 238 1,067 708 3 38 46 15 55.99
Ronnie Brown MIA 147 648 444 3 28 14 1 54.04
Ray Rice BAL 254 1,338 719 2.8 33 78 25 48.92
Ahmad Bradshaw NYG 163 777 480 2.9 23 21 8 48.86
Michael Turner ATL 178 875 594 3.3 27 6 0 48.69
Adrian L. Peterson MIN 315 1,394 915 2.9 50 43 10 48.60
Jamaal Charles KC 190 1,120 687 3.6 28 40 3 48.52

Bottom 10, Elusive Rating
Name Team Att. Yds. YCo YCo/Att. MT Rec. Rec. MT Elusive
Rating
Chester Taylor MIN 93 332 203 2.2 2 44 3 8.03
Derrick Ward TB 115 414 256 2.2 4 20 1 8.15
Thomas Jones NYJ 332 1,402 701 2.1 14 10 0 8.60
LaDanian Tomlinson SD 223 733 425 1.9 9 20 2 8.60
Brandon Jackson GB 37 112 70 1.9 0 21 3 9.83
Larry Johnson KC 132 380 294 2.2 5 12 2 10.69
Glen Coffee SF 83 226 184 2.2 4 11 1 11.70
Brian Westbrook PHI 61 274 126 2.1 4 25 1 12.21
Mike Bell NO 172 653 386 2.2 10 4 0 12.50
Jerious Norwood ATL 76 254 158 2.1 4 19 2 13.26

 

I'm actually not surprised by this at all. We knew Coffee wasn't very good, and despite the well-documented woes of the offensive line Coffee barely did half as well as Gore. 

Gore's Elusive rating is 20.17 which would put him in the bottom half of the league, and I agree with that. Gore isn't the most elusive back--what he has is a quick burst out of the line of scrimmage, but he doesn't make people miss often. 

 

Football Outsiders ranks the top 15 running backs thusly:

1. Chris Johnson
2. Ryan Grant
3. Ray Rice
4. Jamaal Charles
5. Pierre Thomas
6. Steven Jackson
7. Jonathan Stewart
8. Ricky Williams
9. DeAngelo Williams
10. Marion Barber
11. Maurice Jones-Drew
12. Adrian Peterson
13. Joseph Addai
14. Cedric Benson
15. Ronnie Brown
20. Frank Gore

They also put Gore in the bottom half of starting RBs.

 

Based on total rushing yards here are the rankings from NFL.com

 

1. Chris Johnson
2. Steven Jackson
3. Thomas Jones
4. Maurice Jones-Drew
5. Adrian Peterson
6. Ray Rice
7. Ryan Grant
8. Cedric Benson
9. Jonathan Stewart
10. Ricky Williams
11. Jamaal Charles
11. Frank Gore

 

So, once that's all said and done where does that leave us? I think that the traditional rankings based purely on yards and TDs can be misleading (see Jones, Thomas for a good example), but they're not necessarily that far off the mark. They tend to not give a complete picture though.

I also find it interesting that though PFF and Football Outsiders take different approaches to it they tend to arrive at pretty close to the same destination. 

 

Update: Sam Monson of PFF (the original author of the piece), has kindly replied to a few questions I had about his methodology. One of the things he did to provide a ratio when there were zero missed tackles is to add one to everybody's missed tackle ratio. The formula for the MT/Rec. Rating is:

[(MT+1)/Receptions]*100. Thus Beanie Wells 12 receptions and 5 missed tackles looks like this:

[(5+1)/12]*100=50.0

 

Also, for anyone interested, the complete spreadsheet is in the PFF forums in this post.  You have to be a PFF member in order to download the file. 

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