Online Ratings System Adjustments

Beginning at 6 AM CDT on Tuesday, June 22, and continuing through until 6 AM Thursday, June 24, US Chess will be conducting a necessary update to its ratings server and system. Any events submitted during this period will be rated after the system is tested and restored.

What’s Going On?

There are two issues in play. One is a programming bug that has been in the online ratings system since it was launched. The K factor is computed incorrectly (1/4 K rather than full K). This essentially means all online ratings are wrong. Most players online ratings will go up, but some will go down.

The second issue comes from the Ratings Committee, and was discovered after reviewing data on how ratings are initialized from other ratings information. They came up with a blended / weighted / time sensitive approach where more recent ratings are given more weight than older ratings. It will look at the other five ratings types plus FIDE and Canadian/CFC ratings. (CFC ratings still have to be set up manually. We do not have cross-links between CFC IDs and US Chess IDs like we do between FIDE IDs and US Chess IDs, so there is a new manual adjustment record type for entering CFC ratings that can then be used for blended initializations.)

The online ratings need to be completely recomputed back to 2014 due to the programming bug. The Ratings Committee wants to use June 1, 2020, as the start of the new blended initialization formula, because that way any (new) players who have an online regular rating but not an OTB regular rating would have their first OTB regular rating based at least in part on their online regular rating.