Why does the rank go down after a lost game?

[flovo]

This thread is outdated since Jul 2017. At this point the OGS rating system changed to glicko2. The rating system changed in many aspects. All info in this thread about Elo on OGS is obsolete.

OGS has a new Glicko-2 based rating system! [2017]

tl;dr We’re switching to a Glicko-2 rating system, which should be great for a lot of reasons. All of your past ranked games have been accounted for during this transition. Hello OGS! For the past several years we’ve been using a rating and ranking system based on Elo developed by the European Go Federation. It has served us reasonably well, but there have been some shortcomings when applying that system in an online setting. Most of the shortcomings can be traced back to the fact that the sy…