FFM:
In addition to the Massey rating and the HHS rating, I looked at Louisville vs Maryland using the Massey power RPI and Elo ratings. I also looked at a few other teams I was interested in: Mississippi Valley State and Coppin State, two dreadful teams, and at Baylor.
I visualized the data using spaghetti plots (yes, that's a thing; feel free to look it up on the internet). Spaghetti plots overlay multiple observations for each individual (in this case, for a team) connected by a line. This technique is typically used for multiple measurements of the same thing across time. When doing that, all of the measurements are on the same scale and there is a natural ordering for the observations. In this application, neither is true. To get everything on the same scale, I transformed each scale to have mean zero and variance one. This transformation not only preserves the ordering within each scale, it also preserves the proportions of the differences between the teams. I ordered the rating scales by attempting to put the most similar scales next to each other.
If you were to plot the exact same ratings multiple times, the lines would be exactly parallel. Plotting ratings that had the same rankings (i.e., the same orderings) but different scores would result in lines that were not parallel, but did not cross. The more lines cross, the more dissimilar the rankings are.
The spaghetti plots are on the first page of the attached pdf file.
Some observations not directly pertinent to question at hand:
- The Massey rating score and the Massey power score are very similar. This is not surprising as the ratings score is derived from the power score.
- One would expect some differences between the Massey scores and the others, since Massey includes all games and HHS, RPI and Elo only include Division I games. This is reflected in the plot.
- The distribution of HHS scores is somewhat more long-tailed, with more observations close to the middle, but also observations further away from the middle.
- The RPI score is very, very different than the Elo score.
Back to the question at hand, Louisville vs Maryland:
- The Elo and RPI scores have Louisville above Maryland, as the Massey rating score does. The Massey power score has Maryland above Louisville, as the HHS score does, but not by anywhere near as much.
- As per Plebe's post, looking at the RPI rankings of the opponents for Louisville and Maryland make it clear that Louisville has accomplished more (page 2 of the pdf), as per RPI. Louisville has a much better record against top 50 teams.
- Looking at the HHS rankings, it is not as clear which team as accomplished more (page 3 of the pdf). Two of Louisville's opponents (Virginia and Central Michigan) are ranked a little lower on HHS and drop out of the top 50, leaving them with a 5-1 record against top 50 schools. Among Maryland opponents, no teams drop out and Michigan drops in, giving them an 7-4 record against top 50 schools; more wins, but also more losses, and a much lower winning percentage (0.833 vs 0.637). The cutoff at 50 is somewhat arbitrary; if you look instead at the top 60, Louisville is at 8-1 and Maryland is still at 7-4. Louisville has both more wins and a higher winning percentage (0.889 vs 0.637) against top 60 teams.
- The Massey power ratings are even less convincing than the HHS rankings (page 4 of the pdf). Similarly to HHS, the shift into and out of the top 50 favors Maryland, but if you look just about anywhere past the to 50, Louisville looks better.
- My overall impression is that the stronger case is made the RPI scores that Louisville has accomplished more, compared to the case made by the HHS and Massey power scores for Maryland.
The two dreadful teams (Mississippi Valley State and Coppin State):
- Mississippi Valley State is substantially better than Coppin State on the Massey ratings, Massey power and HHR scores, about the same on the Elo score, but much, much worse on the RPI score (page 1 of the pdf).
- As can be seen from looking at the HHS, RPI or Massey power rankings (pages 2, 3, and 4 of the pdf, respectively), MVS has won only one of their games while Coppin State has lost all of their games, however, Coppin State has lost to much better teams.
- To be clear, the Coppin State games against those opponents that were ranked higher than MVS's highest ranking opponent were not competitive. They lost to South Dakota by 38, to Rutgers by 74(!), West Virginia by 35, South Dakota State by 53, Dayton by 30, and Cincinnati by 46.
- The two teams had one common opponent: Florida A&M, which is another dreadful team (their highest ranking on these five rating scales is 343). Mississippi Valley State defeated Florida A&M by 1 point at home; Coppin State lost to Florida A&M by 10 on the road. I don't know what the home court advantages were, but it's hard to believe that they would account for an 11 point swing.
- It makes very little sense to me that RPI has Coppin State so much above MVS. Coppin State has apparently gotten a boost by being routed by some good teams, however, my intuition is that Coppin State did nothing in those games to indicate that they were remotely comparable to those good teams. Providing a boost for getting routed by good teams does nothing toward evaluating how good a team is.
Baylor:
- Baylor is kind of the anti-Coppin State. They are ranked first on all of the rating scales, except for RPI where they drop down to fifth (page 1 of the pdf).
- Baylor has only lost one game, to South Carolina on a neutral court (when their best player was injured and unable to play), which rates no lower than third on any of these five scales (not shown). That's a better worst loss than South Carolina (Indiana - neutral court), Oregon (Arizona State - away), Louisville (Ohio State - away), and Stanford (Texas - away) and comparable to Connecticut (Baylor - home) .
- RPI appears to be docking Baylor for scheduling and beating six ranked below 200, all at home. Six sub-200 opponents is more than any of the teams in the previous bullet, and the other teams played at least one sub-200 team on the road.
- I agree that beating awful teams at home should do little, if anything at all, to build one's resume, but I don't see (functionally) assessing a penalty for that. Squandering an opportunity on a bad opponent should be penalty enough. Assessing a penalty also does nothing towards evaluating how good a team is.
The Massey rating scales, the HHS rating scale and the Elo scale all appear to be different assessments of how good a team is, but the above comparison of MVS/Coppin State and the examination of Baylor suggests that RPI is not trying to do that. Are they trying to evaluate success in the NCAA Tournament (i.e., more experience against better teams will help against the better teams in the Tournament)? What are they aiming for? Also, since the only way for bad teams to get better in RPI is to play good teams and good teams playing bad teams is penalized by RPI, RPI is structurally making it more difficult for bad teams from getting better.
Notes:
- The Massey ratings were obtained from the Massey site: Massey Ratings - CBW. The team schedules were obtained from each team page on that site. Here's an oddity: the cutoff for inclusion in the ratings is games played by 11:59 pm EST. Hawaii played a home game on 1/30 that was scheduled at 7 pm local time, which is midnight on 1/31 EST. That game was not included in the 1/31 report.
- I'm getting HHS ratings from the Her Hoops Stats site: Her Hoop Stats Rtg National Team Leaderboard | NCAA Division I Women's Basketball | Her Hoop Stats. The individual team schedules are from the Massey site.
- I'm getting the Elo rating from Warren Nolan site: ELO Chess Ranking 2020 Womens College Basketball | WarrenNolan.com. The individual team schedules are from the Massey site.
- Lastly, I'm getting the RPI data from the Warren Nolan Site: RPI (Live) 2020 Women's College Basketball | WarrenNolan.com. The RPI rankings are given on that page (twice), but the RPI score for each team is only on the team site. It takes about 2-3 minutes for my program to retrieve the rankings for 351 teams. It would be easier to get them from the Real Time RPI site, but I have lost faith in quality of their data. For about 3 1/2 weeks in January 2020, they included UConn's loss to Louisville on 1/31/18 (no, we didn't play Louisville this season, that's a game from last season). RTRPI finally fixed that, but they're still including Savannah State in the rankings, a school that in no longer in the MEAC, having made the transition from Division I to Division II this year and has no games scheduled against Division I opponents.
- All programming and analysis was done in R.