Originally Posted by maggmaster
I don't understand, you will improve just by playing at that level. Just play and let the ratings fall as they do.
I agree, I was just pointing out why it is "normal" for someone to win all (or nearly all) their matches at 3.5 and then turn around and lose all (or nearly all) their matches at 4.0. I noted this will happen unless they improve, and like you say, playing at a higher level is one of the better ways to improve so they likely will unless they have reached their peak or aren't motivated to do so or any number of other reasons.