Rankings Explained

How the Ratings and Rankings are Calculated

There are three factors that determine a player's rating (W = Wins, D = Draws, GP = Games Played):

• Win points P = (log10 (W + ½D + 1))
• Winning Percentage W% = (W + ½D) / GP
• Strength of Schedule S = (average of all opponents' W%)

The formula for your rating is R = (P * (W% + S)/2) * 100

This year, for the first time, we will also include "legacy points." This means 10% of your rating from last year will be added to your rating from this year.

• Example 1: Pablo

Pablo has played 15 games against a number of different opponents. His record is 7-6-2

Pablo's Win Points P= .95

Pablo's Winning Percentage W% = .53

Pablo's Strength of Schedule S = .50

Pablo's Rating is .95 * (.53 + .50)/2 * 100 = 48.9

• Example 2: Freddy

Freddy and Tom are friends. They come every week, but they only play against each other. In these games, Freddy wins most of the time. Freddy is 8-2-0, and Tom is 2-8-0

Freddy's Win Points P = .95

Freddy's Winning Percentage W% = .80

Freddy's Strength of Schedule S = .20

Freddy's Rating is .95 * (.80 + .20)/2 * 100 = 47.5

Note that even though Freddy has more wins and a better winning percentage than Pablo, Pablo has a higher rating. This is because Pablo's strength of schedule is good. He plays against lots of different opponents. Freddy's strength of schedule is poor because he has only played against Tom.

• Example 3: Tom

Tom and Freddy are friends. They come every week, but they only play against each other. In these games, Freddy wins most of the time. Freddy is 8-2-0, and Tom is 2-8-0

Tom's Win Points P = .47

Tom's Winning Percentage W% = .20

Tom's Strength of Schedule = .80

Tom's Rating is .47 * (.80 + .20)/2 * 100 = 23.5

• Example 4: Alice

Alice is a new student. She showed up one week and won two matches against two good players. Her record is 2-0-0

Alice's Win Points P = .47

Alice's Winning Percentage W% = 1.0

Alice's Strength of Schedule S = .60

Alice's Rating is .47 * (1.0 + .60)/2 * 100 = 38.2

Alice is rated higher than Tom, but lower than Pablo and Freddy. Even though she is undefeated against strong opponents, she only has two games to show. If she came back next week and did the same thing, her rating would rise to 55.9, higher than both Pablo's and Freddy's.