Drafting RBs

Can solid running backs really be found anywhere in the NFL draft? Years ago the conventional wisdom seemed to be that a team needed a superstar RB from the first round to win consistently. Now it seems that the conventional wisdom is that teams still need a star ball carrier, but one can be found deep in the draft. So which is it?

Data

The data consists of RB draft picks from the 1980 through 2000 drafts found at Pro-Football-Reference.com. Running back career performance was judged three ways. First, I averaged the likelihood a RB would be selected to one or more Pro Bowls by round and draft order. Second, I averaged career Yards Per Carry (YPC) by draft round and by draft order. (I also tried various ways of including receiving yards, but the variance in Yards Per Reception is very large and it distorted the data, particularly for players with relatively few receptions. Ultimately, simple YPC worked best and aligned closest with how most people see RBs. That is, Steve Sowell and Dave Meggit aren't ranked above Barry Sanders, Thurmond Thomas, or Emmit Smith.) And lastly, I averaged the number of years as the primary starter by round and by draft order.

Pro Bowl Selection

Although Pro Bowl selection is a flawed measure of career performance in many ways, it can indicate that a draft pick has "panned-out." If you sort the data by PB selection, it very quickly separates the generally productive RBs from the "three yards and a cloud of dust" guys. After looking at PBs for a number of positions now, it seems that 2 or more PB selections is a particularly good measure of career productivity, especially when judging top draft choices.

The graphs below illustrate the likelihood that a RB will be selected to one or more, two or more, and three or more PBs. The first graph is by draft round, and the second graph is by RB draft order (i.e. 1st RB taken, 2nd RB taken, etc.)




I wouldn't read too much into the spike at the 5th RB taken. It's likely just a statistical quirk, but it might be one reason why many experts believe that later round RBs are as good as early round picks.

[Edit: Some have asked why I brushed off the spike of Pro Bowls at the 5th RB taken as a quirk. If we analyze enough draft picks for various positions, as I'm in the process of doing, we're bound to see a significant bunching like this by chance once or twice. The graph is relatively continuous except in one place, where there is a depressed result at the 4th and 6th pick and the spike at the 5th. What is likely at work is that positive results in the 5th pick "bin" have randomly "stolen" positive results from the 4th and 6th bin. There were 20 RBs taken as the 5th RB in the data set, so it would only take 2 or 3 RBs who would otherwise have been the 4th or 6th pick to be bunched into the 5th pick to give us this result. Unless we had a reason to believe there is some special quality about the 5th RB taken before seeing the results, we should not interpret the data to say there is something magical about being the 5th RB taken.]

Yards Per Carry

There is probably no simpler and truer measure of running back performance than yards per carry. Of course, YPC does not belong to the RB alone. For any one RB's season, offensive line ability has a tremendous influence on his stats. But over 490 careers and over 24 years of data, the abilities of offensive lines will average itself out to a great degree, leaving career YPC a reliable estimate of true RB performance when grouped by round or draft order.

As with QBs, the biggest question is how to score draft picks with no carries or very few carries. RBs with fewer than 200 career carries tended to have extreme YPC stats. I assigned them the YPC of the 5th percentile qualifying RB, which was 3.58.

The two graphs below break out career YPC by draft round and by draft order.

The first round RBs, particularly the first couple taken, tend to significantly outperform later picks. By the 3rd or 4th round and the 7th RB taken, teams are likely getting sub-replacement level special teams fodder.

Also notice the nearly 1:1 relationship between career YPC and PB selections, including the spike at the 5th RB taken. This suggests that PB selection is merit-based and is a reasonable proxy for grading career performance.

Scouting Accuracy

How often do the scouts get it right? In other words, how often does the higher pick turn out to be better than the next pick? The two table below lists the likelihood that the higher pick will have a better career YPC than the next RB taken in the same draft. We shouldn't expect the scouts to be perfect, but this table tells us how difficult it is to predict the better player.















RB PickPr(Better)
10.62
20.67
30.57
40.48
50.55
60.33
70.43
80.33
90.33
100.38


Years as Primary Starter

Another way of judging the value of draft picks is the number of years the pick has served has his team's primary starter. Top RB picks, especially the first two each year, tend to serve much longer as a primary starter.














RoundYrs as Primary Starter
14.1
22.7
31.5
40.7
50.8
60.6
70.5


















RB PickYrs as Primary Starter
15.0
25.1
33.2
42.4
53.7
61.6
71.9
81.4
92.7
101.0
11-220.8


Conclusion

Top picks solidly outperform subsequent picks. The top two RBs taken tend to almost be in a class to themselves, then there is a steady decline in expected performance until the 8th RB taken, at which point there is very little to be expected from a pick.

So do teams need a superstar #1 pick RB to win, or can they find a premier runner deep in the draft? Which conventional wisdom was right? My theory is it's neither.

I think most people still grade RBs in terms of total yards, whether it's for a single game or for a season. Even though it should be well known now that winning leads to running, rather than vice versa, commentators and analysts continue to count 100 yard games or 1000 yard seasons as measures of RB effectiveness.

But even below-average RBs on winning teams with good passing games and good defenses will tend to accumulate large chunks of total yards due to frequent carries. Even a RB who was a 5th round pick on a great passing team will appear much better than he truly is. I believe that might explain the perception that solid RBs can be found anywhere in the draft.

The better RBs really do come from the top picks. It's just that they're not that important, or at least they're not as important as they were in the 1970s before the NFL became a passing league. Plus, our understanding of which RBs are truly the very good ones is distorted by analysts who insist on total yards as the best measure of RB performance.

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7 Responses to “Drafting RBs”

  1. Rasmus says:

    Nice article, just like the QB one. Are you planning on writing one about WR's too?

  2. Brian Burke says:

    Thanks. Yes, I'd like to get to WRs before Saturday, but right now I'm working on DEs. Don't want to ignore the other side of the ball.

    Really only after we see how all the positions compare through the rounds will we be able to make any conclusions about optimum draft strategy.

  3. Anonymous says:

    After your research I am quite certain you will find O-line the most consistent performers. In particular LT.

  4. Anonymous says:

    Love the analysis overall,hate the inclusion of Pro Bowls as a barometer of how good any player is RB or otherwise.I know its just one part but it honestly means almost nothing as to judging talent and success rate over time.

    The Pro Bowl is nothing more than a popularity contest these days,and to me the number of Pro Bowls a guy goes to is worthless.Yes in some cases the numbers will jive especially with the best of the best who perform year after year,but I could count those guys on one hand.If you are a big name star,you get voted in even in off years when you dont deserve it.If you arent a big star,chances are you wont get into a few Pro Bowls you deserve to be in.

  5. Anonymous says:

    RBs are very important, and I also dispute your claim that winning--->rushing and not the other way around.

    In 2008, for example, the 4 RBs with 90+ rushing yards per game were Adrian Peterson, Michael Turner, DeAngelo Williams, and Clinton Portis. The Falcons, Vikings, Panthers, and Redskins all ranked 14th-25th and were below the mean in team passing yards in 2008, so none of them were a result of riding the coattails of great passing games.

    In 2007, only 3 RBs averaged 90+ rushing yards per game: Adrian Peterson, LaDainian Tomlinson, and Brandon Jacobs (with Brian Westbrook and Willie Parker ranking right behind them). None of those were even average passing games, either (except for the Eagles). If winning leads to rushing, then the Patriots, Colts, Cowboys, and Packers should have been among the leading rushing teams, but none of them were.

    The Vikings were a losing team before Adrian Peterson arrived. Then he had one of the best rookie RB seasons ever followed by an even more impressive season in 2008. He took over and won at least 3-4 games in that 2-year stretch for the team by himself.

    The Panthers were 5 games worse in 2007 (7-9) while starting the ineffective DeShaun Foster instead of DeAngelo Williams (who averaged 1.5 more yards per carry). In 2006, they were 8-8 with a healthier Delhomme, the 15th ranked passing offense, but still rushed for fewer yards than they did in 2007 or 2008. The Panthers were 7th in points scored and 1st with 30 rushing TDs. (The Falcons ranked 10th in points and were 3rd with 23 rushing TDs.)

    The 8-8 Redskins ranked 8th in rushing yards and attempts in 2008.

    It's probably more accurate to say that losing necessitates more passing, especially in the second half. Even when NFL teams choose aggressive passing strategies, they still need a quality RB (Edgerrin James, Priest Holmes, Marshall Faulk) to prevent double coverage, not allow DBs to sit back in zones, and discourage the front 7 from sending 5-6 guys after the QB on every play.

  6. Brian Burke says:

    You're citing total passing yards and their league ranking above, which you point out later is not a good indicator.

    Running is important, just not as important as passing. And when it comes to total running yards (instead of running efficiency), winning certainly does lead to more total yards. Not sure why someone would even dispute that.

    The fact is a standard deviation improvement in passing leads to far more wins than a standard deviation improvement in running.

  7. Mike S says:

    What an insightful article. Very informative. I fully agree with your assessment that average RBs are made to look better then they are due their year end rushing totals brought about by the increased opportunities afforded them by their winning teams.

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