I attempted only one question in july lunchtime 2017 and got wrong answer
consequently no place in ranklist i.e. “YOU DID NOT PARTICIPATED IN THIS CONTEST”
still my rating decreased significantly (-192)
and also my rating graph and bar representation did not change but only rating did!
@admin please correct it!
there must be other people with same error.
you can post your comment here
As far as i know, even if you get 0 points, that contest will be considered for your rating. I remember another instance where someone who wasnt able to get even partial AC got his ratings reduced under same circumstances. Why it shows “You did not participate” is a altogether different story.
The rating not reflected in graph is with everybody.
Why does my graph show no participation for Cook-Off and Lunch Time, though I’ve participated in each of these and it’s even showing my ratings for these ?
Also my rating says 1631, but below that there’s Max Rating, which still reads 1475.
Same happened with me. This is because of the controversial problem of the cookoff.
Yes I think that ratings are not calculated correctly
My highest lunchtime ranking was 319 but in JULY Lunchtime I got 232 rank still my rating decreased. 
@anushi I am quite sure that decrease or increase in rating depends upon your overall rating and not on the rating in that specific competition. Correct me if I am wrong.
Check: https://www.codechef.com/ratings
Your lunchtime rating has increased as your rank this time is better than the previous lunchtime but the overall rating decreased as the overall expected performance was supposed to be better.
3 Likes