All users’ ratings have been recalculated for all contests from SNCKPE21 (Nov 2021). This has been done after all cheaters in these contests have been penalized and moved to the bottom of the respective contest ranklists. This is done to make the ratings fairer for the non-cheaters.
So now you don’t have cheaters at the top of the ranklists, leaching away rating points from the non-cheaters.
The large increase in ratings are for users who had been wrongly penalized in plagiarism (false positives), and hence now been reversed.
After removing the cheaters, and the false positives:
- ~125000 users have an increase in their ratings
- ~290000 users have no change in their ratings (mostly inactive users)
- ~6000 users have a decrease in their ratings
Amongst the users with an increase, the maximum increase is 225, and 99% of them have an increase of less than 125.
Amongst the users with a decrease, the maximum decrease is 96, and 99% of them have a reduction of less than 60.
The rating reduction is mostly in cases where the users have had a string of bad performances, and the lower penalized ratings of the cheaters in their subsequent contests adversely affects these non-cheaters.