Codeforces rating system is based on ELO, which is a great system. But divisions cause a bit of trouble with it. Candidate masters are the best od Div 2. They usually get good positions at contests, and that causes them to get a very big rating change. Then they will turn International Master or high Master, which can be bad. Of course when they participate in Div 1 their rating will converge again. The graphs of people who are converging at CM usually get a very big jump at the end, and that is not how the model should work. I'm not suggesting to remove divsions, maybe just twist the formula a bit or something. I don't have many experinece with rating systems tough.
Thanks for reading!
I think it is best to revert to the system where purple was only in div1. This will surely solve this problem.
The problem will be the same to experts then. The problem was when purple coders participated in Div 2.
There is a difference Experts are not allowed in Div1. And you will reach candidate master from Expert not Master or International Master as there is 200 rating slab of CM which is not easy to jump.
Agree
The current system is really confusing. Introduction of div 4 gave us many specialists who wouldn't be specialists otherwise.Similarly div 3 is giving us many experts who wouldn't be experts otherwise.
Also, this year after quarantine started, I feel like my rating got inflated more than it should have. I don't think I have improved much since few months back when I was in 1700s, but I rose up to 1900s recently.
And also a strange thing I felt is : it's easier to maintain CM rating in Div1 contests rather than Educational or Div2 only.
After becoming a specialist you can't participate in div4 any more so if you are not deserving then your rating will surely converge. The same is the case like experts and div3. The only difference is with the Candidate Master, which can't be helped. Making Purple only Div1 is not a good choice as they still can't solve all div2 problems and reducing rated contests for them will be not good.
The problem is, many people only do cp here to get to a certain rank and then leave. Some of the pupils and newbies I've seen, when they got specialist from div 4, then they stopped competing to protect that rating.