26 July 2008

FIDE Cleans Its Rating Data

Continuing with FIDE Struggles with the Growing Popularity of Ratings, I started that post with a small anomaly in the data.

A count of players for each year:-
1997 - 22.670
1998 - 20.916
1999 - 30.204

I discovered that FIDE erroneously dropped many names from the rating list between January 1997 and January 1998, then added them back in January 1999. The number I derived was 4.329. Adding these to the 1998 count from the previous table reveals a different story.

1997 - 22.670
1998 - 25.245
1999 - 30.204

This shows 4.959 more players in 1999, or a 20% increase in the number of names from 1998 to 1999. It is a large increase by the standard of previous years, but not too unusual compared to later years. The 1999 list was the same that saw the introduction of FIDE IDs to identify players. I assumed that these observations are somehow related and started to look at the new names on the 1999 list.

When I identified players on the 1999 list who were missing from both the 1997 and 1998 lists, I found 7.636 names. Of these, 853 were titled players, including 467 IMs and GMs. Looking at those names a litle closer, I found that FIDE cleaned the format of many names between 1998 and 1999. For example, 'Akhsharumova, Anna..M' in 1998 became 'Akhsharumova, Anna M' in 1999, 'Amura, Claudia.N' became 'Amura, Claudia N.', 'Darchia, Diana' became 'Darcia, Diana', and so on.

One little mystery I encountered was GM Dimitri Anagnostopoulos (GRE). I found him for the very first time on the 1999 list with a 2450 rating, but he was missing from all previous lists. I also found 'Dimitri Agnos (GRE)' on the 1997 and 1998 lists, with a rating over 2450, but he was not on the 1999 list. Then there was 'Demetrios Agnos (ENG)', similarly rated, on lists up to 1996. Were these all the same player? If so, this highlights FIDE's need to introduce the FIDE ID to identify players uniquely.

Continuing, I also counted 2.942 players on the 1997 and 1998 lists who were missing from the 1999 list. These included Akhsharumova, Amura, etc. Subtracting this number from the 7.636 names added in 1999, gave 4.694 new players. This compares favorably with the increase of 4.959 players I calculated earlier, and is as accurate as I want to get with this exercise.

Starting in 1999, I have FIDE IDs to work with. No more messing around with names!

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