@NolanL

> Why did I lose rating points? I tied for second and was the last one to be checkmated (game #1723888)

your avg opponent: 1231

tie for 2nd-3rd:

(2w+1l + 2l+1w) /2

so 1.5 wins and 1.5 losses vs 1231 = -X

if you'd had low deviation of 70 or so, perhaps you'd gotten -5 or so. your high deviation of 104 explains the -13.7.

4 Player chess uses the glicko2 rating system.

FFA:(0<=X<=1. X gets smaller the higher the average rating of all players)

1st: 3 wins

2nd: X wins

3rd: X losses

4th: 3 losses

vs average rating of the game.

As a result, rating changes for 2nd an 3rd place are smaller in higher rated games.

Solo:

1st: 4 wins2nd-4th: 1.33 losses

Players that are

tied for pointsshare the number of wins and losses for the tied positions.Teams:Each team receives a "team rating" first, which is calculated as follows:

Higher rated player in team * (2/3) + Lower rated player * (1/3)

In other words: A

team's rating is weighed 2/3 toward the higher rated player.Each player then gets one win or one loss vs. the opponents "team rating".

Rating

DeviationakaGlicko RD= "Confidence that the rating is accurate".Players with very few gameswill have a high deviation and thus theirrating changes will be large.Players initially being with a deviation of 120, which will slowly drop to around 65 as more and more games are played. This allows players to reach their "true rating" quickly.

Hover over ratings in the player popup to see the deviation (Glicko RD)

Ratings with a deviation greater than 100 are marked as provisional by a "?"

In other words,

the "?" indicates the player has not played many games yetand his rating is likely not very accurate.A player's rating deviation only has an affect on the player's own rating changes, but not on those of his opponents, or his teammate.

Old (outdated) rating thread: https://www.chess.com/clubs/forum/view/how-the-rating-system-works