How are players ranked?

Two scores are determined for each summoner/champion/role (one for the current season, one for the past 30 days). Then a third score is computed (geometrical average of the two previous scores). Summoners are ranked by champion according to their best "averaged score" (one averaged score per role) for that champion.

The two scores (the one for season and the one for past 30 days) are computed using those rules: