Is the USATT Rating System Inflationary, Deflationary, or Stable?
I don't have exact numbers on this, but it's fairly obvious that, over the years, the ratings have inflated. When I started out in 1976 there were only three players rated over 2400 (Danny Seemiller, D-J Lee, and Gil Joon Park, with the latter two from South Korea); now there are 116, and this is only among USA players. There are more foreign players now listed as USA players than before, so this is part of the reason, but the bulk of these 2400+ players are just as much USA players as those back in the late 1970s. Dan Seemiller had just reached top 30 in the world with a rating just over 2500. Insook Bhushan (then Insook Na) had just come to the U.S. from South Korea, and was top ten in the world among women, but was rated only about 2250. These days top ten in the world among women would be about 2650. At one point I was 18th in the country among U.S. citizens with a 2292 rating; these days it wouldn't make the top 100. So yes, the ratings have inflated. (My impression, however, is that any inflation has decreased or stopped in recent years. For one thing, the highest rated USA players now are actually a bit lower than some from the previous generations, but that's offset by the fact that the previous generations had players with higher world rankings and deserved the higher ratings.)
But wait, some of you are thinking, hasn't the level of play improved, and that's why there are so many more higher-rated players these days? That modern players have improved is absolutely true - but that has no bearing on the ratings. As players on average improve, so do their opponents. Think of it this way. If everyone were to suddenly improve 100 rating points in level, there would be no effect on the ratings themselves since opponents would also be 100 points better. And so even though everyone's about 100 points better, the ratings themselves would stay the same.