Brief Comments on January Ratings

The newest update to the ratings is reflective of a change in the methodology of the ratings.  The ratings now include a much wider range of tournaments but exclude rounds with participants whose rating would not be reliable due to lack of representative opponents.  The reasoning and method are described in this blog post.  The tournament results now included are listed on the ratings page.

A couple of reactions to the new ratings:

First, Oklahoma Ard & Cherry reveal something of a difficulty for the ratings, one which hasn't been fully resolved.  Though I don't release them, the true bearers of ratings are actually not team partnerships, but rather individual debaters, whose ratings are then averaged to produce the team rating.  A strength of this arrangement is that it allows debaters to get credit no matter who their partner is.  As a result, Oklahoma AC's rating has evolved even though the two of them have not debated together since the last ratings update.  The difficulty for the ratings calculation is that the way that it deals with individual debaters joining up with new partners that have significantly different ratings is not necessarily perfect.  The original design of the Glicko ratings was for one-on-one competitions like chess.  Debate complicates this with its 2 person teams.  This is not a problem for teams that stick together, but it does present some difficulty for those that change partners.  The way that the ratings currently deal with this issue is to more heavily weight each individual's own rating but factor in the rating of their partner as well.  Thus, for example, when Ard debates with Chiles, Ard's rating will grow more slowly than Chiles's will with each win and drop more with each loss.  The disparity in their ratings will shrink over time if they continue to debate together.  However, the ratings also don't treat Ard the same as if he were still debating with Cherry.  He will be rewarded slightly more for wins and punished slightly less for losses given the rating's knowledge that he is debating with a lower rated partner.

Second, the big winners with the update include Minnesota CE, Wake Forest LS, Kansas HR, Towson TW, Michigan DM, USC BL, KCKCC CN & CJ, and WSU MO.

Third, Harvard DH continues to outpace Harvard BS.  This demonstrates both a strength and weakness of ratings like these.  BoSu's season has been stellar by any measurement, making it to 2 finals and 2 semis and accumulating only 4 losses.  DH's results have also been top notch, but they haven't made it to any final rounds and have a lower overall win percentage, though they did win the Kentucky Round Robin.  DH certainly has a lot of very good wins, but their (single point) lead on BoSu has more to do with the fact that they've done very well at six tournaments as opposed to BoSu's four.  BoSu's position is due to their relatively small sample size.  They just haven't had as much time to prove themselves.  My impression is that this will probably work itself out before long unless BoSu decides to not travel again before the postseason.  Number of rounds matters less and less over time, but since all teams start the season with the same default (1500) rating, it does take some time for each team to differentiate itself.