Predicting RB Touchdowns

Using the same methods detailed in the last few posts, I started looking at how running backs' touchdowns are affected by age and experience.

First, a look at td percentage (per carry) as a function of player age:
This curve looks OK, with a slight Fred Taylor effect, but an unexplainable notch appears at age 24.

Now for td percentage as a function of player experience:


This one makes perfect sense. Rookies and 2nd-year players do OK, then see a huge spike in year three. After that, it is more or less all downhill.

If we calculate the RMS error of simply using a player's last two years stats to predict next year's TDs, we get 4.56 TDs of error. Using age, the number falls to 3.66, and using experience, the error is 3.18 TDs.

Once again, it appears that using a combination of previous years' stats and player experience gives us the best prediction of future player performance. This is heartening, since that is the same thing we found when looking a RB yards per carry. Hopefully, we have come across a method that will work for all positions.

Next up: Wide receivers.