dmac80 wrote:Why do these RPI rankings vary so much? PC is in the 20s in CBS and ESPN but in the 40s in this one?
edit: the up to the minute RPI ranking is in the 20s but if they try and guess where they'll be later (or at seasons end) it might be lower than that. I'll stick with the current up to the minute over projections, there are too many teams involved for that imo.
http://www.rpiforecast.com/live-rpi.html
RPI Is a garbage rating to begin with, but is especially so at this time of the year because of the relatively small number of games and the varying quality of opponents.
RPI Forecast does something different than the other RPI rankings do. They apply the current predictive power rating from Sagarin to the remainder of the schedule, using a complex formula that processes up to 10,000 simulations through their computers. It combines both the future projections and the actual results of games already played. This gives a far improved calculation for a couple of reasons:
1. The Sagarin predictive power rating includes point spreads in its calculation,which is more reliable than the W/L% and SOS basis for RPI.
2. By applying Sagarinto future games, RPI Forecast improves its reliability by using a larger sample size and by reducing variability in schedules. Its limitation obviously is that this is only a statistical projection of future games and not based on actual results, so the RPI it projects will change as more games have been played.