2021 RPI and NCAA Tournament Bracket

Discussion in 'Women's College' started by cpthomas, Aug 28, 2021.

  1. cpthomas

    cpthomas BigSoccer Supporter

    Portland Thorns
    United States
    Jan 10, 2008
    Portland, Oregon
    Nat'l Team:
    United States
    In doing one of my big annual update projects, I ran into these two charts when I got to BYU. They provide an interesting commentary on the RPI. There is an explanation below each chart.

    upload_2022-1-14_10-35-21.png

    This chart shows team RPI ranks as compared to their Massey ranks. I use Massey because he has ranked team for a long time and I have been able to evaluate how his ranks correlate with results in comparison to how RPI ranks correlate. The Massey and RPI correlation rates overall are about the same, but Massey does significantly better at rating teams from different regions and conferences in relation to each other. The Massey data base, to a limited extent, reaches back in time beyond the current season. In addition, Massey takes game scores into consideration.

    As you can see, Massey (blue) pretty consistently has ranked BYU better than the RPI (red). In addition, the chart shows how, within the RPI formula, BYU has ranked as a contributor to other team strengths of schedule (gold). How BYU ranks as an RPI SoS contributor should be the same as how it ranks in terms of the RPI itself. As you can see, that is not the case a good deal of the time.

    upload_2022-1-14_10-44-31.png

    This is the chart that really caught my attention. It evaluates the strength of BYU non-conference opponents. The Massey average rank of its opponents is blue and the RPI is red. In addition, the gold shows the strength of schedule contribution BYU opponents make to the BYU RPI, based on the RPI formula. As you can see, Massey consistently ranks the BYU opponents as stronger than the RPI does and both rank the opponents as stronger than the contributions the RPI recognizes them as making to the BYU RPI.

    Although I am not a fan of using NCAA Tournament results as a basis for evaluating rating systems, it probably is worth noting that this year the end-of-regular season RPI rank for BYU was #26. For Massey, it was #6. The discrepancy almost certainly is due mostly to the RPI woeful inability to properly measure the strength of BYU schedules.
     
    L'orange repped this.

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