100 Fantasy Football Tips in 100 Days, Day 7: Regression in Rushing YPC
A couple days ago, I posted a sample from my book Fantasy Football for Smart People: What the Experts Don’t Want You to Know that detailed why “overworked” running backs don’t really “break down.” I explained that the dip we see in YPC is usually due to regression and selection bias, not because the running back is overworked. Here’s more analysis from that chapter:
Knowing that the selection of backs with 350-plus carries in a season is naturally skewed toward those who were healthy and effective has profound implications on our conclusions. Naturally the outliers from the previous year, these backs are likely to regress toward the mean, independent of their workload. That is, running backs who have a high YPC are likely to regress in the following season whether they got 350 carries or 100.
That idea is supported by the stats. When examining the relationship between YPC in Year Y and Year Y+1 among all backs, we see a trend similar to that of the high-workload rushers alone.