Running Back Touchdown Regression - Also A Sure Bet

Earlier this month, I posted a study that investigated touchdown regression over the last three seasons at the wide receiver and tight end positions. The results were very telling, as over 90% of the players in our sample regressed (both directions) the following season.
 
Today, I’ll be doing basically the same thing, but, instead of focusing on Reception / Touchdown rate, I’ll study the Carry / Touchdown rate for running backs. In an effort to keep the two pieces as consistent and as easy-to-follow as possible, I’ll be using the same format.
 
To create an appropriate sample size, I pulled the data on all running backs from 2008 through 2010 who racked up 75+ carries in a single season. In both 2008 and 2009, 61 players accrued 75 or more carries. In 2010, that figure dropped to 57 players.
 
Note that, in order to increase our sample size as much as possible, this study will use data from playoff games.
 

Going Down

Next, we will pull out the players in those samples who put up a 4.5% or higher touchdown rate. Considering the league average TD rate for running backs is right at 3.1%, this would be considered high. Over the last three seasons, 38 players fit the bill, 12 of who achieved the feat in 2010. That cuts our sample to 26. Two players failed to carry the ball at all the following season, which leaves us with a grand total of 24 players worth investigating.
 

The chart above shows each of our 26 (I included the two backs who went without a carry in the following year) players' carry total and TD rate during the season noted in Column 1. ‘Next Car’ and ‘Next TD%’ refer to the carry total and TD rate the player put up the next season. Finally, we have the ‘Change’ column, which shows us the difference in the player’s TD rate from Year 1 to Year 2.
 
If you learned anything from the WR/TE study, it should be that TD regression is as real as it gets. This holds true again today as a whopping 22 of the 24 (92%) backs in our sample saw touchdown regression in Year 2. The exceptions were Falcons Michael Turner, who enjoyed a rare 1.0% increase to 5.6% in 2009 and Tim Hightower, who saw a jump of just 0.2% between the same years. Note that both backs show up in the list twice, as regression finally caught up with them in 2010.
 
Additionally, we see that 18 of the 24 (75%) backs fell below the 4.5% threshold in the second year. You may have noticed that most of these players with high touchdown rates are known as tough, between-the-tackles runners. Interestingly, the two backs most likely to not fit that description (Leon Washington, Reggie Bush) suffered the two largest drop-offs in Year 2. I can assure you that it’s not a coincidence.
 

Going Up

Next up, we take a look at players who suffered a 1.5% or lower TD rate. Considering our aforementioned 3.1% league average rate, anything below 1.5% should be considered poor/unlucky. 35 players fit our conditions, with nine of them doing their thing in 2010. That brings us down to 26. From there, we need to eliminate players who had zero or only a handful of carries in Year 2. This eliminates nine more players, leaving us with a sample of 17 players.
 

The results aren’t quite as convincing, but they are convincing nonetheless. 14 of the 17 players (82%) enjoyed a better TD rate in Year 2. Two of the three players who saw a decline dropped less than 0.2% and, similar to earlier, all three exceptions show up twice in the sample, regressing (or in Jamal Lewis’ case, not playing at all) the following season. The other two were Julius Jones (-0.1%, +1.5%) and Derrick Ward (-0.2%, +7.1%).
 
14 of the 14 (100%) players who saw an increase in their TD rate also enjoyed a Year 2 rate that was above our 1.5% threshold. In fact, all but one (Steven Jackson) eclipsed 2%. Eight of the 17 (47%) enjoyed a Year 2 rate above the 3.1% league average.
 
At the end of the day, literally every single player we mentioned today eventually regression in the touchdown department. Most of them did in year 2 and the last few came through in year 3.
 

2011 Losers

Twelve players make the cut for 2011, each managing a 4.5% TD rate on 75+ carries in 2010. If we use the last two seasons as a guide, 92% (or 11 of the 12) of the listed players will suffer regression in 2011. A new column appears here, as well, called ‘Proj TD%’. This indicates the TD rate I’m currently projecting for each player in 2011. Notice that of the 10 I currently have projections built for, nine show a drop. The only exception is John Kuhn, who I anticipate will see fewer carries overall, but a higher percentage near the goal line.
 

2011 Winners

Nine players fit the bill in 2011. All racked up, at least, 80 carries last season and had a TD% at or below 1.5%. My projections show an increased rate for all seven players currently on an NFL roster. Once Brandon Jackson and Ricky Williams land on a roster, it’s a sure bet that they’ll both be projected at a rate at or above 2%.
 

Final Thoughts

Like I said in this section last time around, there is no getting around TD Regression. When it comes to very high and very low rates, it’s all but a slam dunk that the numbers will regress. You’ll always have your large, tough backs on good teams who consistently enjoy above average rates and small, quick backs on poor teams who rarely score, but even those players will score enough to stay out of the “danger zones”.
 
In closing, I’ll leave you with the success rates of the four tests I ran over the last two weeks.
 

 
 
Follow Mike on Twitter: @PFF_MikeClay … as well as our main Twitter feed: @ProFootbalFocus
 
 
[Editor's note: you can also find this article, along with the rest of Mike's work, in our PFF Fantasy section.]