A problem has been reported and confirmed with the July 2018 rating supplement data. While we determine the nature and extent of the problem, and as a precautionary measure, we have removed the July 2018 rating supplement files from the website.
We hope to have this problem resolved by Monday evening.
The problem with the July files has been corrected and revised supplement files for July have been posted. Anyone who downloaded the files prior to Sunday morning should update their systems.
It looks like there may be a problem with the August supplement files. These two players show having an otb blitz rating in the August supplement but their tournament history shows no otb blitz tournament for them:
It looks like there is a potential for this to happen if the only events for a player in a specific ratings system are deleted or the player ID is changed. In this case, a blitz event was rated and then deleted in late June, after the July ratings list was created but before the August list was created.
How many records this affects and what to do about them will require further testing. (A complicating factor is that there are many players for whom we have no ratings system detail, because they have not played in a game rated since 12/8/1991, but who do have an old but still publishable rating in that ratings system.)
This issue has existed since 2005, but has not been reported by anyone prior to this, so fixing it doesn’t seem urgent. It looks like in a typical month it may affect a dozen or so players. (Most months over 20,000 players have an updated rating.)
As the number of recently active players affected is generally small, this may not get corrected prior to the generation of the September rating supplement, in part because it is not yet clear what the appropriate means to correct it is, and that may require testing on a separate system. This does not affect the computation of anyone’s rating for non-deleted events that they actually played in.
I think I have the program that generates the rating supplement records changed so that it won’t do this with deleted events or revised IDs in the future, I do not know if we will attempt to retroactively update supplement records. It looks like there may be about 2000 member records affected over roughly 18 years, and quite a few of those are duplicate IDs that are no longer in use. (The most common reason for changing an ID in an event is because someone discovers it was a duplicate and the office changes the event records to use the correct member ID.)
Thanks Mike
I’ll try to remember to check it on the 16th after the September supplement run, but I have some personal/family matters to attend to that will limit my time for several weeks. I’ve advised the ED of the issues in retroactively updating supplement records, whether US Chess wants to allocate resources to dealing with that is her decision to make.
I checked both of the players cited upthread who had blitz ratings in August that were the result of deleted events, both will be correctly listed as unrated in Blitz in September when those records are posted later today.
Thanks Mike