Rating recalculation after penalizing cheaters

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.


Thanks Codechef!!!

Thanks Codechef… will start giving contests again


Always wanted this from the start that ranklist should be updated after plag check.
Thanks @admin for this.


Now this is something good from Codechef.

A great decision from CodeChef

Thanks Codechef for taking this action.


This is one of the best things codechef did​:partying_face::partying_face:
Thx a lot :fire:
Feeling much more motivated to give contests now​:fire::fire::fire::fire:


Thank you CodeChef I :heart_eyes: love You :revolving_hearts: :two_hearts: :sparkling_heart:

Thank You Codechef

CodeChef being CodeChef. Thanks!!

this is best thing , i hope u keep the same mechanism for each upcoming contests, so that each contest could be fair, and people could no more say that there are cheaters filled on codechef.

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Got 104+

If I would have been given 32 more I could achieve 6* lol

Anyways good step codechef!!! :raised_hands::raised_hands:


I’ve taken part in 26 contests after december but my rating is unchanged, why is that so? @admin

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My overall rating has increased by 158. 4 more to 6*.

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so let’s say I became 5* on CodeChef with an increase in rating but that puts in the div1 system, so other starters contest will not be rated for me after that intermediate 5star rating

yah they increase rating even for starters

may be because when we given that contest at that time we are in div2