what decides a rating increase or decrease after a match on this site?

Sort:
Avatar of Mommedb

also, is your opponent's rating considered?

Avatar of baddogno

Not only is your opponent's rating considered, but it's accuracy as well.  The site uses the Glicko rating system.  I took the liberty of doing a Search Forums for Glicko RD (rating deviation).  I'm sure others can explain it better than I would.  Oh, if you're handy with calculus and such, the exact formula can be found with a Google search.

http://www.chess.com/forum/search?keyword=Glicko+RD

Avatar of r_k_ting

Glicko is just algebra, no calculus involved.

(I am compelled to make one smug comment related to mathematics every day. My apologies.)