Is Glicko biased?

Sorry for the short answer. Somewhere on the forum are lengthy explanations how the rating system works.

The rating system is not biased in one direction. If it would be the case, OGS would have a big problem with rank deflation.
Rating changes are calculated using

  • your rating, deviation and volatility at the begin of a rating period (volatility is not shown on OGS)
  • the current rating and deviations of all of your opponents in that rating period
  • the info if you won/lost the games.

A rating period consitsts of up to 15 games.

The rating change is antisymmetric in rating difference (losing against a 100 points weaker opponent = - winning against a 100 points stronger opponent)

Neither reason for win/lose nor the score have any impact on rating changes

There is more about the rating system

And the math of glicko