Earlier today on CBSsports.com, Matt Norlander wrote an article about the much-maligned RPI. He comes to this conclusion:
If anything else, this chart proves there are far too frequent communication breakdowns with teams across the board, enough so that the RPI goes beyond outlier status and continues to prove what many have known for years: If the RPI was introduced in 2012, it’s hard to reason that it would be adopted as conventional by the NCAA or in mainstream discussion.
Norlander then provides the heart of his argument, a table comparing the RPI to various other basketball ratings: Sagarin (overall), KenPom, LRMC, Massey and BPI. He points out that “Texas, Belmont, Arizona and Southern Miss all have big disparity as well. The largest gaps are UCLA (62 points lower in the RPI) and Colorado State (65 points higher in the RPI).”
The RPI is a rating created to measure what a team has accomplished so far this season based on their record and their strength of schedule. It is a descriptive rating. LRMC, Massey, BPI, and Sagarin are predictive ratings at their core (though some are even worse, a random combination of descriptive and predictive). Comparing the RPI to these ratings and concluding that because it doesn’t match, it is flawed, is itself a terribly flawed argument. Of course it doesn’t match, it is trying to measure a completely different thing. I agree, the RPI is flawed, but not because of this.
Norlander’s article should have been about his preference for selecting and comparing teams based on their true strength instead of their resume, and not about the quality of the RPI which has little to do with this debate. Even if the RPI perfectly did it’s job (of measuring how much to reward teams for their performance on the season), it would have failed the test in this article. Let’s take a deeper look. (more…)