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Kevin Bonham
22-10-2009, 06:59 PM
In his latest outburst in the other place firegoat7 (David Beaumont) was whinging about some ACF ratings being out of line with FIDE ratings given that the ACF ratings officers are authorised to make adjustments for FIDE-parity.

Those adjustments are made for FIDE-parity at the higher end of the ACF pool, not the area around FIDE 2000 where rampant over-rating by FIDE has been rife for many years as a result of FIDE's use of ratings floors and discarding of sub-floor data. Although FIDE have now dropped the ratings floors many players remain FIDE-overrated as a result of them.

firegoat based his whinging about parity on the following:

1. His own FIDE rating being 200 points higher than his ACF.
2. When Bill commented on his (Bill's) rating having effectively lost the 220 points added in two uplifts, firegoat wrote:


the same deflation has occurred to almost every player who was given the rating manipulation at the same time. Tino Fulgenzi and Katrina [sic] Wills must be just rolling their eyes.

Wills is an extremely unrepresentative example since she performed very much below her old rating in a single tournament after being inactive for a long time. I don't know anything about Fulgenzi.

Beaumont's FIDE rating is extremely unreliable as he has only had games rated by FIDE in four periods in the last seven years. He performed to his FIDE rating in the 2005 Victorian Championships, lost 52 FIDE points in the Elwood Bendigo 2008, lost 28.75 FIDE points in the Ballarat Begonia 2009, and lost 6 FIDE points in the 2009 MCC Champs.

So most likely the reason his FIDE has not gone down as much as his ACF is simply that he has played too few FIDE games for his FIDE rating to match his declining reliability of performance.

I had a look at the CV and NSWCA ratings for the current period compared to just before the first of the two uplifts. Among CV players with surnames from A to F, the average points difference was 122 points net gain. If firegoat's comments were accurate one would expect the average to be about zero but it clearly isn't. Among NSWCA players in the same surname range it was 77 points net gain.

By comparison for the sixteen Tasmanian players on both lists the average points difference was 46 points net gain. While this very small sample may be seen as giving some support to Phil Donnelly's view that there is serious deflation in Tasmania induced by juniors, it doesn't. The reason it doesn't (apart from the very small sample size) is that the median age of the players on both lists is probably about 63. At an estimate, five of the Tas players on both lists are over 70, four in their 60s, two in their 50s, four in their 40s and I am the youngest of the sixteen at 37. If the system says the average player in their early 60s loses 17 points a year in playing strength, is that really so unreasonable?

That's not to say there's no deflation in Tassie; I think there may be a little bit. But it doesn't stand out as starkly as one might expect from Phil's comments.

CameronD
22-10-2009, 11:29 PM
I think another factor between ACF and FIDE ratings are that most ACF games are 60+10 compared to way longer for FIDE ratings. Some peoples ability may jump by huge margins with the extra thinking time

Kevin Bonham
22-10-2009, 11:37 PM
I think another factor between ACF and FIDE ratings are that most ACF games are 60+10 compared to way longer for FIDE ratings. Some peoples ability may jump by huge margins with the extra thinking time

That would be interesting to look at - if that is true (which it very probably is) then there will be some players whose ACF performance ratings for FIDE-rateable time limits are much better than at faster limits.

Vlad
23-10-2009, 11:07 AM
I think another factor between ACF and FIDE ratings are that most ACF games are 60+10 compared to way longer for FIDE ratings. Some peoples ability may jump by huge margins with the extra thinking time

This is a very valid point due to the fact that 60+10 allows to have 3-4 games a day, while 90+30 allows only 2 games a day at best.

After a certain number of hours of play players get tired and the result of a game has less and less to do with skills but rather more about luck (with the caveat that older people usually have less luck:)). Given that ACF rates such events, while FIDE does not it implies that there could be significant differences between the ratings.

Kevin Bonham
26-10-2009, 04:30 PM
After this weekend I am certainly of the view that my performance suffers in 60/10 events with crammed schedules rather than 45-60 mins break between rounds! Or perhaps that's just an excuse for shoddy play. :(