I have prepared fantasy football ratings for the 2014 NFL season based on the data from last year’s season. I hope you will find them useful! You can download the ratings here.
These ratings are reasonable but flawed. The strengths of the ratings are:
- They are based on player performance from the 2013 season, using a somewhat standard fantasy scoring system. (6 points for touchdowns, -2 for turnovers, 1 point per 25 passing yards, 1 point per 10 passing yards, and reasonable scoring for kickers.)
- The ratings are comparable across positions because the rating means the expected number of fantasy points that a player will score compared to a “replacement level” player for that position. I call this “Fantasy Points Over Replacement”: FPOR.
- Touchdowns are a key contributor fantasy performance, but they are fickle: they often vary dramatically between players of the same overall skill level, and even between seasons for the same player. In a previous post I showed that passing and rushing touchdowns are lognormally distributed against the yards per attempt. I have accounted for this phenomenon in the rankings. Loosely speaking, this means that a player that scored an unexpectedly high number of touchdowns on 2013 will be projected to score fewer in 2014.
- The ratings do a rough correction for minor injuries. Players that play in 10 or more games in a season are rated according to the number of points they score per game. Therefore a player who missed, say, two games in 2013 due to injury is not disadvantaged compared to one that did not.
There are several weaknesses:
- I have data for several previous seasons but do not use it. This would stabilize the ratings, and we could probably account for maturation / aging of players from season-to-season.
- Rookies are not rated.
- We do not account for team changes. This factor is often very important as a backup for one team may end up as a starter for another, dramatically affecting fantasy performance. (I actually have a pretty good heuristic for accounting for this, but I have not implemented it in Python…only SAS and I no longer have access to a SAS license.)
- Players who missed a large portion of the 2013 season are essentially penalized for 2014, even if they are expected to return fully.
- I have not rated defense/special teams.
You may want to adjust the rankings accordingly. Here are the top 25 rated players (again, the full ratings are here):
FPOR is the adjusted, cross-position score described earlier. RawPts is simply 2013 fantasy points. AdjPts are the points once touchdowns have been “corrected” and injuries accounted for.
We will see how the ratings work out! If I have time I will post a retrospective once the season is done.