At times I wonder if ratings are like what they say about sausage, that it's better to not see them getting made. The process is one of gradual fine-tuning, and I hope that my openness about it has at least been interesting for some.
The final ratings for the pre-first round bid period are now posted. There is one fairly significant change to the way that the ratings are calculated, which should address the concerns that some (including myself) have addressed that the ratings don't adequately evaluate elimination rounds. I'm not going to go into a ton of depth (districts prep weighing down), but a short explanation should at least cover the big picture.
Previously, elim results were tabulated as a percentage of the ballot count of the panel. Thus, a win on a 3-0 would be 100% (or 1), a win on a 2-1 would be 67% (or .67), etc. This seemed logical and fair for a couple of reasons. First, a 3-0 is a stronger win than a 2-1. Second, it seemed like the loser of a 2-1 should get some credit.
However, based on an analysis of last year's data (and some eyeballing of this year's ratings), this solution isn't the most accurate of options. For those who have some stats background, I tried mapping ballot counts onto a log function, which would give a boost for the win, and gradually even out with more disparate ballot counts. That worked better, but what I ultimately found out is that the most accurate predictions came from the ratings where elims were treated in the same binary manner that prelims are. In other words, the ratings are most accurate when specific ballot counts are disregarded and the results just counted as a win or loss. The new ratings reflect this change.
How to deal with elims will be a continuing issue that I will look at down the road. It is something that might require creative solutions and will certainly involve lots of testing.
A couple of other notes:
1. The new ratings exclude any team that hasn't been together for at least 3 tournaments as a unit.
2. The ratings do include all of the round robins, but to minimize some distorting effects of the early round robins, I made the ratings pretend that they occurred after the regular Weber & Kentucky tournaments.
3. Strictly speaking, these ratings are not intended to be predictions of first round voting. However, it will be interesting to see how well they match up. My impression is that the most recent update will be more in line with voter tendencies than the previous version.
4. There's a problem with KSU's Klucas & Scott that I need to fix, but it will have to wait a few days.