PDA

View Full Version : Beginner Questions:: Ratings

MikeCPharmD
06-23-2009, 06:09 AM
I had a couple of general questions about something people seem to take for granted: Ratings:
1) How are ratings calculated?

2) When results of tournaments are displayed, there are +/- numbers after the players' rating. What is the significance of these numbers? (Looking at Ebutaljib's post on the history in the 2008 Championships, the +/- was about 2% of their ratings--The 2007 matches in Elista, Russia showed Gata Kamsky and Etienne Bacrot showed that +/- number more 12% of their ratings at the time.)

3) How quickly and to what degree do ratings change? (Again, by looking at Ebutaljib's post in history, if I look at the results from Elista, Russia, Levon Aronian was at 2759 during the qualifiers but in the actual World Championship he was 2750. Boris Gelfand remained at 2733 throughout. Alexander Grischuk was at 2717 in the beginning, but despite only getting 5.5/14 in the Championship tournament, he went up to 2726.)

MikeCPharmD
06-23-2009, 06:09 AM
I had a couple of general questions about something people seem to take for granted: Ratings:
1) How are ratings calculated?

2) When results of tournaments are displayed, there are +/- numbers after the players' rating. What is the significance of these numbers? (Looking at Ebutaljib's post on the history in the 2008 Championships, the +/- was about 2% of their ratings--The 2007 matches in Elista, Russia showed Gata Kamsky and Etienne Bacrot showed that +/- number more 12% of their ratings at the time.)

3) How quickly and to what degree do ratings change? (Again, by looking at Ebutaljib's post in history, if I look at the results from Elista, Russia, Levon Aronian was at 2759 during the qualifiers but in the actual World Championship he was 2750. Boris Gelfand remained at 2733 throughout. Alexander Grischuk was at 2717 in the beginning, but despite only getting 5.5/14 in the Championship tournament, he went up to 2726.)

KHollister
06-23-2009, 06:50 AM
Look at the Chessmaster Grandmaster Edition FAQ (http://forums.ubi.com/eve/forums/a/tpc/f/4221052685/m/3211095046)... it will explain how the ratings are calculated. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Ebutaljib will have to explain the +/- numbers in the crosstable... I'm afraid I don't know. http://forums.ubi.com/images/smilies/blush.gif

As to how quickly ratings change... your rating will change every time you play a rated game. However, keep in mind that in professional chess, the "official" list of ratings is published by FIDE four times a year, so someone's rating might actually be higher (or lower) than the currently published rating.

ebutaljib
06-23-2009, 07:54 AM
1) Which ratings do you mean? Ratings in Chessmaster (in that case follow the link that KHollister gave) or official ratings published by FIDE - World Chess Organization?

You can read about FIDE ratings (ELO) here (http://www.fide.com/component/handbook/?id=73&view=article). It isn't quite that complicated as it looks http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

2) Those numbers represent rating performance in that particular tournament. Let's look at the table of recently finished Karpov tournament in Poikovsky: