Women's NCAA Basketball RAPM

Regularized Adjusted Plus-Minus

Jesse Fischer • October 20, 2018
Photo: Lorie Shaull

Regularized Adjusted Plus-Minus (RAPM)

After bringing RAPM to the men's college basketball game, I wanted to do the same for the women's game.

Process

RAPM calculations rely on knowing how performance changes when players are on and off the court. Unfortunately, anyone who has played around with NCAA data knows that this is not an easy process (large number of teams, inconsistent player names, missing substitutions, etc.). Nevertheless, I have done my best to convert raw NCAA play-by-play data into possession "stint" data (similar to this).

While RAPM is an objective calculation, there are endless enhancements that you can perform to improve performance or learn unique insight. I have tried to keep my RAPM calculations as vanilla as possible, however it is worth noting that I am (1) controlling for home court advantage and (2) filtering "garbage time" possessions. Over time I may explore other extensions (e.g. coach impact, team specific HCA, Bayesian prior adjustment, further fine-tuning regularization).

NCAA Basketball RAPM Reliability

Given the smaller samples sizes for college basketball, I was unsure how noisy the RAPM results would be. One quick sanity check is to look at year-to-year consistency of RAPM across seasons, which I have been pleasantly surprised with. For example, across each season of her college career, RAPM consistently had Brittney Griner as a top-ranked player on both ends of the floor. For comparison, I included a handful of other recent top draft picks.

To improve RAPM stabilization further, I have also calculated "multi-year" RAPM which utilizes all available years of data (currently 9).

Results

Download complete RAPM results (currently updated for 2010-2018 seasons):

WNBA Draft Picks

Select your favorite draft class to see how RAPM viewed future WNBA players (in their final college season):

Top Players

Check out the top-rated players in O-RAPM, D-RAPM, and overall RAPM:

Teams

Select your favorite team1 to see if RAPM results align with your expectations:

  1. The team views are currently limited to the top 30 teams (based on highest cumulative RAPM). Feel free to download the raw data to look closer at a team which wasn't included or reach out on Twitter if you think we should build an interactive view which allows you to pick your own custom filters. ↩