From the front of the annual rating list, I had assumed that anyone with more than 25 rated games had an established rating. However I recently discovered a provisional rating based on 33 games. I haven’t looked through all 12 of the events, but as the rating is 100/33 I’m guessing that she’s lost all of her games. Does an established rating now also require at least one win or draw?
Check the ratings formula (the link is at uschess.org/ratings) for details on the ratings formula, including why it may take more than 25 games to get an established rating under the formulas that have been in effect since around 2000.
Can you be more specific?
So far, the only links there that I’ve found that mentions the issue is:
math.bu.edu/people/mg/ratings/approx/approx.html
which reads:
“Players’ ratings are considered provisional if they have played 25 or fewer games (rather than 20 under the old system), and established if having played more than 25.”
and in:
math.bu.edu/people/mg/ratings/rating.system.pdf
“A player’s rating is termed ‘provisional’ if it is based on 25 or fewer games and is ‘established’ otherwise.”
It does talk about the ‘special’ and ‘standard’ ratings formula applications, but that does not appear to have anything to do with use of the terms ‘provisional’ or ‘established’.
From what you’ve posted those quotes as well as what appears on the front of all of the Rating Supplements since 2000 have been incorrect. Or the implementation of the rating system which sometimes considers players with more than 25 games as provisional is incorrect.
It appears that player has lost every game so far (30 as of the annual list, now up to 33.)
I don’t have access to my notes right now, but as I recall a player stays under the special formula (and provisionally rated) as long as he or she has lost (or won) every game. I’ll check with Mark Glickman on that when I get a chance.
From my reading of his article, the player would stay under the special formula until winning (or drawing? possibly) a game. I’m not sure why that means they wouldn’t become established. Provisional vs Established seems now to be a separate distinction based upon number of games played from which formula to use for calculating their rating. (Unlike the previous implementations where provisional and established had different rating formulas.)
I heard back from Mark Glickman. Once a player has reached 25 games he or she should be shown in the official rating list as having an established rating, even though the ‘special’ formulas still apply if that player has lost all of his or her games. There are about 4 recently active players for whom this applies, plus two cases I found of what appear to be database issues that I’ve asked Walter Brown to investigate later this week.
I’ll have to fix this in the programs that report the official ratings, such as MSA, since I need to keep the ‘has lost all games’ status in the rating system until that player wins or draws a game. I should have this corrected for the February Rating List.