100 Fantasy Football Tips in 100 Days, Day 43: Regression, Randomness, and Running Backs
Today’s tip comes via a sample from my book Fantasy Football for Smart People: How to Dominate Your Draft:
Back in 2008, I had running back Thomas Jones ranked well ahead of most owners. Jones was playing for the Jets and coming off a season in which he ran for 1,119 yards, but averaged just 3.6 yards-per-rush and scored only two total touchdowns. Those two scores represented just 0.59 percent of Jones’ 338 touches in 2007. ESPN had Jones ranked 21st among all running backs. I had him 10th. Why would I possibly rank a then 30-year old running back coming off a season in which he tallied 3.6 yards-per-carry and two total touchdowns in my top 10? Regression toward the mean. Regression toward the mean is a phenomenon wherein “extreme” results tend to end up closer to the average on subsequent measurements. That is, a running back who garners 338 touches and scores only twice is far more likely to improve upon that performance than one who scored 25 touchdowns.
0-16 Detroit Lions: A Coach’s Dream?
Regression toward the mean is the reason the NFL coaches who take over the worst teams are in a far superior position to those who take over quality squads. If I were an NFL coach, there is no team I would prefer to take over more than the 2008 Detroit Lions. Coming off an 0-16 season, the Lions were almost assured improvement in 2009 simply because everything went wrong the previous season. Even though Detroit was a bad team, any coach who took over in 2009 was basically guaranteed to oversee improvement in following years. The same sort of logic is the reason that there are so many first-round “busts” in fantasy football. Players almost always get selected in the first round because they had monster years in the prior season. In effect, most first-rounders are the “outliers” from the prior season’s data, and their play is more likely to regress than improve in the current year. It isn’t that those players are poor picks, but rather that the combination of quality play, health, and other random factors that led to their prior success is unlikely to work out so fortunately again.