NCAA TOURNAMENT: KEEPING THE RPI HONEST, PART 7

 In Parts 1 and 2 of this series, I described a test to see if this year’s RPI will be usable.  The test compares the Top 60 and Top 30 in the RPI rankings to baselines for the Top 60 and Top 30 derived from 2013 to the present.  It looks at two groups of conferences: a highlighted group consisting of the eight conferences that have had at least one team in the Top 60 every year since 2013 (ACC, American, Big East, Big 10, Big 12, Pac 12, SEC, West Coast) and a not-highlighted group consisting of all the other conferences.  The test shows the average number of teams and the high and low number of teams each group has had in the Top 60 and Top 30 since 2013.  It asks the question of how the numbers for the RPI ranks this year compare to the test period numbers.

Top 60 Test:  The RPI Top 60 should include roughly 49 teams from the highlighted conferences and 11 teams from the not-highlighted conferences.  The actual numbers can range on either side of these test numbers, but 45 teams should be the minimum from the highlighted group and 15 the maximum from the not-highlighted group.

Top 30 Test:  The RPI Top 30 should include roughly 28 teams from the highlighted conferences and 2 teams from the not-highlighted conferences.  The actual numbers can range on either side of these test numbers, but 27 teams should be the minimum from the highlighted group and 3 the maximum from the not-highlighted group.

Here are three different looks at how these tests apply to the current season, for games played through Sunday, April 4.

 ACTUAL RPI, TO DATE

The following table shows conference representation in the RPI Top 60 and Top 30, plus totals for the highlighted and not-highlighted conferences at the bottom.  The left portion of the table is based on actual RPI ranks, to date, and the right portion of the table has the historic baseline test numbers.

The following table is similar but for regional playing pools:

ACTUAL RPI, TO DATE, CONFERENCES PLAYING SOME NON-CONFERENCE GAMES

Here are similar tables, but for this year’s RPI Top 60 and Top 30 if I consider only conferences playing at least some non-conference games.  I include these tables because it is indisputable that for conferences that play no non-conference games, the RPI cannot rank their teams in relation to teams from other conferences.

SIMULATED RPI, USING ACTUAL RESULTS TO DATE

Here are similar tables, but based on the entire season, including conference tournaments.  Their underlying data are the actual results of games played through April 4 plus simulated results of future games.  These should give a pretty reliable picture of what the end-of-season numbers will look like.

COMMENT

As the above tables show, the RPI is going to greatly underrate teams from stronger conferences and regions and greatly overrate teams from weaker conferences and regions.  This is due to teams not playing enough total games, not playing enough non-conference games, and not playing enough out-of-region games.  Further, it is true even if one considers only teams from conferences that are allowing members to play non-conference games.

As we get closer to the end of the season, this does not seem to be changing.