From Lichess page 'Chess rating systems':


Which rating system is best?


The purpose of rating systems is to predict the outcome of games. Therefore, they can be objectively better or worse, according to their ability to make such predictions. Glicko 1 makes better predictions than Elo, and Glicko 2 makes better predictions than Glicko 1

My question: Is 'predict the outcome of games' the same thing as 'reduce the number of upsets' ?

Upset here is simply lower rating defeating (or drawing against?) higher rating. Thus, assuming all ratings are integer valued and no 2 players of equal rating play against each other, what I understand is that

'1800 is more likely (or at least as likely) to beat a 1700 if the ratings are glicko 2 as compared to glicko 1'

if and only if

'Glicko 2 makes better predictions than Glicko 1'

Is there anything I misunderstood?

  • 1
    Basically correct. (Note that these rating systems don't natively deal with draws.) Nov 20, 2021 at 0:53
  • @MobeusZoom thanks! what's up with the draws please? (or do i have to make another question for this part?)
    – BCLC
    Nov 20, 2021 at 1:00
  • @MobeusZoom you can post as answer even if incomplete. i'll award bounty but i guess just not accept bounty. looks like no one's really answering anyway
    – BCLC
    Dec 20, 2021 at 17:04
  • 1
    ok. Not sure it is incomplete. You asked if your understanding is right, and it is Dec 21, 2021 at 11:59

1 Answer 1


Basically correct. (Note that these rating systems don't natively deal with draws, only with binary wins/losses. Draws are incorporated by summarizing results as point-score = wins + 0.5 * draws.)

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