There are several Malaysian chess bloggers or anonymous commentators who try to promote the fiction of 'ratings inflation' at every opportunity. For example, they'd say a 2300 rating 20 years ago is equal to 2400 nowadays. As we say in Malay, that is 'cerita karut'. So I did some research to see how widespread this misconception is.
To my pleasant surprise, the hot topic in chess forums and articles worldwide on this matter discuss ratings deflation that is especially pronounced at the 2000-2200 range. Even FIDE recognises this ratings deflation issue from a long time ago. Links to forums discussing ratings deflation: wikipedia, rybka forum, chess.com.
I suspect that it is only a few Malaysian chess oldsters who is out to promote themselves by saying that our younger players are weaker than they were a long time ago. Actually, a 2400 rating only 15 years ago is probably about 2350 nowadays. and a 2200 rating say 20 years ago is unlikely to be more than a 2000 rating nowadays.
Inflation only at the top end
The idea of ratings inflation was first presumed at the top end of the range, when the ratings of the world's best players appeared to be increasing with time. At first glance, it should not be because FIDE rating is supposedly a 'zero sum' system. If a player gains rating points, another player must lose ratings points. So over time there should not be any inflation overall.
However the observation is that there is clearly inflation at the top end So if the top players' ratings are going up, then someone else must be losing ratings points. The logical conclusion is that there must be ratings deflation elsewhere within the ratings range.
Deflation at the lower end of the range
So, even from a long time ago, those who studied these matters had come to the conclusion that there is ratings inflation at the top end which is balanced out by ratings deflation at the lower end. The question then moves to what I call the 'inflection point', where deflation stops and inflation starts. When I was researching this matter a few years ago, my estimate was an inflection point around 2500.
However, some two years ago, FIDE commissioned the statistician, Jeff Sonas, to do a study using the ratings data provided by FIDE. Mind you, it was 100% data and not just a sample which make it a comprehensive study. Surprise, surprise, the inflection point was found to be just below 2700. This means something like say, comparing ratings over a 5-year period, it could be:
5 years ago Now Difference
2780 2788 8
2750 2756 6
2720 2724 4
2700 2702 2
2695 2695 0
2660 2659 -1
2600 2597 -3
2500 2495 -5
2400 2393 -7
2300 2290 -10
2200 2185 -15
2100 2075 -25
Thus, in this example, 2780 five years ago has been inflated to 2788 in today's ratings, On the other hand, ratings deflation has caused a player with 2100 strength five years ago to drop to 2075 now even though there may not be any drop in playing strength. This situation is applicable to a mature player who plays regularly especially against opponents within say a 200 point ratings difference. 30 games a year should be the norm for 'regular play'.
For a player who plays less than 30 rated games a year, the likelihood is that his rating does not reflect current strength. So for a mature player who hardly plays, a 2400 rating 10 years ago could be worth less than 2300 nowadays. And a 2200 rating 20 years ago is probably less than a 2000 rating nowadays.
So if an 2200-rated (20 years ago) player who has been inactive (but still play at the strength as 20 years) now comes out to play say 30 games within a one-year period against a mix of opponents in the 2000-2400 range, it is likely that his rating will quickly drop to below 2000 to reflect today's higher standards.
This article is written at the request of Fong Yit Ho who wishes to ensure his contemporaries are not misled by the propaganda of some 'old' Malaysian players who are always saying that they were stronger than the younger Malaysian players at the same age . They do this promoting the fiction of 'ratings inflation' thoughout the whole ratings range which is clearly a falsehood.