One year ago today, I introduced my True Fantasy Points (TFP) system. (If you haven't read it, stop and click on that link. I'm not going to go into methodoligical minutiae here.) Using TFP is a four-step process:
- Calculate a player's "true" efficiency stats via the application of a basic regression to the mean technique. This adjusts the stats to account for their inherent randomness, essentially separating skill from luck.
- Multiply the player's "true" efficiency stats by his opportunity volume (i.e., passes, runs, etc.) as projected by our very own David Dodds. This results in a player's projection for "true" stat totals.
- Use a scoring system -- in this case, Footballguys standard scoring system -- to convert the player's projection for "true" stat totals into TFP.
- Compare the player's TFP to his Dodds' point projection to gauge how much, if at all, Dodds is over- or under-estimating the player's "true" efficiency.
Just so no one's confused from this point forward, I'll give a preview of what's to come by using Matt Ryan as an example. In 4,530 pass attempts with the Falcons, Ryan has produced a Yards per Attempt (YPA) of 7.23, a touchdown rate (TD%) of 4.46%, and an interception rate (INT%) of 2.36%. These three efficiency stats differ with respect to how inherently random they are, which means that 4,530 attempts has given us a better gauge of his "true" skill in a relatively stable efficiency stat like YPA than his "true" skill in a wildly volatile efficiency stat like INT%. After taking this into account via regression to the mean (Step 1 above), we arrive at Ryan's "true" efficiency stats: 7.25 True YPA, 4.56% True TD%, 2.39% True INT%.
From there, the math is pretty simple. As of July 27th, Dodds projects Ryan to throw 570 passes. If we multiply each of his "true" rates by 570, we get a projected "true" stat line of 4,131-26-14 (Step 2). Converting that into standard Footballguys fantasy points (and adding in Dodds' 73-0 rushing projection), Ryan's projected to score 304.1 TFP (Step 3). Now compare (Step 4). Dodds projects Ryan to score 305.9 points, or 1.8 points higher than his TFP projection. As you'll see, this is one of the smallest differences among quarterbacks this year, which means we can conclude that Dodds' projection properly reflects Ryan's "true" skill as it relates to scoring fantasy points in 2016. If the difference was much higher, say +20.0, we'd conclude Ryan's being highly overestimated due to the unlikelihood that he wildly overachieves his True YPA, True TD%, and/or True INT% -- and vice versa.
In terms of the accuracy of my TFP system, this is only its second year, so a broader assessment will happen when I have more data. That said, reviewing last year's article, it did remarkably well at the margins. Picking a specific cutoff to delineate where exactly "the margins" are located would be disingenuous of me, but if you click on the link and take a look for yourself, you'll see more and more hits than misses as you move towards either end of the TFP table.
Alright, so let's dive into this year's numbers...