Why sometimes star rating decreases because of single questions done in competition in cookoff types of challenges ? Is there a need to show improvement in star rating??
Stars depend on your rating, which in turn depend on your rank in contest. You can improve it by continuously achieving better rank than the codechef rating mechanism expects you to obtain.
Please find detailed description on ratings here
Basically you need to perform better than the expected rank calculated by the system. Also, rating depends on how many people whose rating is less than yours and ranked above you.
Yes It decreases if your performance is relatively less than previous one.
To see that that your rating will increase or decrease after a particular contest then you can see this link
so if you don’t want your rating to be decreased then see the above predictor and as it reaches above the
previous rating then your rating will not decrease.
Thanks , I Hope It Helps You.!!