Finding Running Backs

In my casual wanderings of /r/nfl, /r/browns and listening to (God help my soul) 92.3 the Fan I keep hearing the same phrase over, and over and over again.  You can find a running back anywhere in the draft.  This is quickly followed by some combination of the following names: Ray Rice/MJD (round 2), Jamaal Charles/DeMarco Murray (round 3!) and Arian Foster (UNDRAFTED!!!!).

Full disclaimer: I am a Brown's fan.  I like the idea of the Browns drafting Trent Richardson with the 4th pick this year.  I like other picks as well, but this one is constantly followed by the words "but you don't draft a running back that high" or "you can get value in later rounds." 

My question is this: what is the failure rate of high RB draft picks?  What is the success rate of low round running backs?  How many Montario Hardesty's are there for that Jamaal Charles?

What I am not trying to answer is the value of a running back in the modern NFL.  Analysts love saying its a "passing league" and running back by committee is the way to go.  Thats fine, but no one will turn down MJD or AP on their team.  No one.  So if you can draft one of them, you will.  Thats the joy of the draft. 

My attempt to answer these questions is purely on 1.) draft position/round, 2.) stats and 3.) career longevity.

Regarding stats:  I want to use stats that reflect individual effort, reduce luck, and stress longevity.

Individual effort I essentially think of as yards.  Rush yards per game and receiving yards per game seem like pretty decent standards of success.  Using a "per game" hopefully biases towards players who play entire games, not just come in for 1 or 2 runs and break a big one.

As far as luck, well touchdowns are pretty lucky.  For a RB to score, they either need good to great field position or they break a big one.  I don't care about poachers.  Scoring with a RB from the 1 or 2 yard line is more representative of the offensive line, in my opinion. 

Longevity... well I probably could have done better on this.  I basically divide played seasons by possible number of seasons.  I include a season's yards from scrimmage to try to enhance guys playing total seasons, not just a hot game or two.

OK enough blathering, onto the data: 
I took every RB drafted from 2006-2011 (I could go farther back, but any trend should be evident over 5 years of data), recorded their draft round and draft position and then took Rush yards/game, Receive yards/game, and Yards from scrimmage for every year they are in the league.  I then average each of these stats over career.

And for funsies, I throw in Arian Foster.  This gives me 90 guys who all have 1-5 years experience in the league.

Fig 1. Average rushing yards per game versus pick number.  Clearly their is a negative trend, however the data is noisy.  The black line is a polynomial fit to the data.  You can think of it as the running average of the data.  Blue dots above this outperformed their draft spot.  Dots below underperformed.

Fig 2. Average receiving yards per game.  The same trend occurs.  This is probably more team specific, but obviously running backs who have plenty of receiving yards are an asset.  Especially in a WCO offense team, like, ahem, the Browns.

Fig 3. Average yards from scrimmage per year.  This is both rushing and receiving yards.  Again the same trend is seen.

Some quick observations looking at the data.  No one selected early (left side of the figures) is as bad as the guys selected late (right side of the figures).  Arian Foster is not plotted as he doesn't have a pick number.  There is a clear negative trend.  The later you pick, the less productive a player you get.  There is essentially no value for anyone picked past 150 (round 5 and beyond). 

Lets look at some of the outliers:

• You see a high point in Rush yd/game at Pick 177 Evan Royster.  He averaged 54.7 yds/game in one season.  He only totaled 404 total yards.  Thats four games.  The jury is out on him.  
• There is an obviously low yds/game at a high pick.  C.J. Spiller has only averaged 27.7 yds/game in his career.  He also has been running behind Fred Jackson.  
• There are tons of zeros.  These guys got hurt or cut (or in a few cases guys who only have kick return stats).  The only populate the graph at picks 50 or higher.  They dominate guys taken in the 7th round.  It would appear that drafting a 7th round RB is almost always a waste of a pick.  

Ok, so right off the bat, I see more value at higher picks.  At least over the last five years.  The other thing I notice is that all high draft picks are at least average and at best they are the best.  There is small variation.  In the middle its a crap shoot.  At the end everyone stinks.

In order to look at this clearer I took the top 32 backs in 2011 and looked at their stats.  The average of these guy's season is ostensibly the gold standard of what you must do in order to start in the NFL next year.  Now we are comparing careers to the top 32 in one year, so careers will always be worse, but it is a good comparison.

Secondly, I wanted to know what percent of the offense one running back accounts for.  I averaged total rushing yards per scrimmage for all NFL teams from 2006-2011 and call this the offense.  I can use this to normalize one running back's contribution to a single game or a single season (Yards per game divided by average rushing yards per scrimmage for all NFL teams).  I call this % offense.

Fig 4.  Percentage of offense by draft round.  The top 32 running backs in the NFL account for roughly 60% of their team's running offense.  The average first rounder accounts for 50%  of a running offense with a standard deviation of 16%.  It only goes downhill from there.  Oh and the standard deviations explode until you are in the basement of round 5 and beyond.

Ok so this figure convinced me.  The guys drafted in round one are consistently good or alright.  No one completely tanks unless you consider being average tanking (and many do).  Rounds 2 and 3 have good players however the misses are just as present.  The error bar for round 2 basically covers the entire graph.  That is not good.  Its a crap shoot in round 2.  You get Ray Rice but you also get Kenny Irons.  Who is Kenny Irons?  I don't really know either.    Round 1 you can get AP or C.J. Spiller.  Spiller should have been a second or third rounder and he would have been a good pick.

Here is where I devolve into the realm of pure speculation.  I wanted to combine the per game stats and per year stats with some correction for longevity.  This is to push the Evan Roysters of the world down and hopefully pull out the best backs.

I hereby define a new quantity I will call the RBscore:

$RBscore\; =\; ((Rush\; yds\; per game)*(Receive\; yds\; per game)\; +\; (Yds\; from\; Scrimmage\; per year))\; *\; (Seasons\; played\; / Possible\; seasons\; played)$
$$
$I\; then\; scored\; every\; player\; (this\; time\; including\; Arian\; Foster)\; and\; ranked\; them\; by\; score.\; Without\; further\; ado\; the\; top\; 10\; are:$

1. Ray Rice - 4169.5
2. Matt Forte - 3948.3
3. Chris Johnson - 3783.7
4. Maurice Jones-Drew - 3381.5
5. Adrian Peterson - 3236
6. LeSean McCoy - 3179
7. Jahvid Best 2808.6
8. Ryan Mathews - 2684.6
9. Darren McFadden 2615.7
10. Reggie Bush - 2251.6

The bottom of that list is a little fishy, but the top is hard to argue.  How does a guy like Jahvid Best (who I in reality like) sneak into the top 10?  Well he has averaged 39 receiving yards per game.  Thats the best of first round picks.  Ray Rice in comparison has averaged 35 receiving yards per game in his career.  

More interesting than this is the question, where were these guys drafted?  I broke the list of 90 into groups of 10 and made pie charts showing their draft round:

Observations from this:

• Top 10 guys are all Round 1 or 2.
• The rest of the Round 2 guys drop to mediocrity to worse
• The rest of the Round 1 guys are at worst in the top half of all guys drafted.  No one has ever gotten worse than a servicable back.  
• The highest surprises are a single Round 4 back (Michael Bush) and one undrafted back (Arian Foster) in the second group.
• Third rounders start to appear in the second tier.  Jamaal Charles, DeMarco Murray and Kevin Smith.  
• 5th round and beyond (with the exception of Foster) are a waste.

So lets break this data up in one final way.  Lets look at the chance of having a "starting season" from a  draft position.  I will call a starting season any season where a guy outperforms the median season from 2011 for a particular stat.  This is the last two bars way back in Figure 4.  Basically you have to account for around 60% of your team's rush offense to be counted as a good draft pick.

I allowed for the possibility of 3 possible "starting seasons" for a guy on any given year.  They can surpass either rushing or receiving yards per game or yards from scrimmage per year.  I then divide by the number of possible seasons * 3 (which is the total possible number of starting seasons).  The closer to one, the better.  Zero is they never perform in any category.  I can multiply this by 100 to get a % of starting seasons.

The top 10 are:

1. Matt Forte - 83%
2. Ray Rice - 83%
3. Adrian Peterson - 80%
4. Maurice Jones-Drew - 78%
5. LeSean MCoy - 78%
6. Chris Johnson - 75%
7. Darren McFadden - 58%
8. Reggie Bush - 50%
9. Ryan Mathews - 50%
10. Jamaal Charles - 50%

And grouping again in groups of 10 sorted by draft round we find:

Only three guys remain with starting seasons, but they do not form a very illustrious list: Mike Goodson (11%), Brandon Jackson (6%) and Lorenzo Booker (6%).

Takeaways from this view are:

• First round is consistent as always.  Only 4 guys have never had a starting season, Laurency Maroney, Donald Brown, CJ Spiller and Mark Ingram. 
• Second and third rounders can definitely be huge hits. 
• Fourth round gives you at best a third tier guy.  Its a total waste.  
• Arian Foster should have been drafted in one of the top three rounds.

Finally, I think I can answer the question I set out to answer.  What percentage of each round are busts?  I think getting at least 1 starting season for each season you play is not a bust.  You are in the top 16 in at least 1 of the 3 main categories for every season in the league.  Thats pretty good.  Clearly, you hope for better in a number 1 pick, but this is the draft after all.

You have a better than 50/50 chance of getting a starting running back in the first round.  Its about 1 in 3 for rounds 2 and 3.  That being said, Round 2 backs are tops of the list.  You have a 6% chance of getting Roy Helu in Round 4.

Looking at all of this data tells me this:

• It is definitely worth drafting a RB in Round 1.
• It is riskier but totally worth drafting a RB in Round 2.
• Round 3 is a suckers game.  You have a 33% chance of getting Michael Bush.  Do not draft anyone who has fallen this low.
• Round 4-7 is for other positions.
• This "value" people find in the later rounds is lie.  The talking heads appear to be wrong.

If I were the Browns, I would draft Trent Richardson and not worry.  Right now they have the 66% of Round 2 (Hardesty and Jackson) in the backfield.  Then again, maybe third time is a charm...

References:

• Draft positions: www.wikipedia.com
• Player stats: www.pro-football-reference.com
• My spread sheet I worked from: RB_draft.xlsx