Formula

The Mississauga SCRABBLE® Club uses a unique formula in order to calculate each player\’s rating change for the Ratings List and Club Championship Standings. The formula was adopted from a system used by the Montreal SCRABBLE® Club, but has since been modified to better reflect skill and create movement in the standings.

Rating changes are determined by several factors: the ratings of the two players before the match, the spread, the result, as well as newcomer or expert multipliers if applicable.

Basic Change

The Basic Change is determined by the ratings of the two players and result of the game, as shown in following table:

If the Favourite (i.e. the higher rated player) wins the match, then the winner will gain as many rating points as shown in the second column, and the loser will lose that many points. For example: If a player, Pierre, rated 1234, wins against a player, Mackenzie, rated 1007, then Pierre will gain 6 rating points, and Mackenzie will lose 6 rating points, since the two players had a rating difference of 227 points.

If the Underdog (i.e. the lower rated player) wins the match, then the winner will gain as many rating points as shown in the third column, and the loser will lose that many points. For example: If a player, Lester, rated 944, wins against a player, Charles, rated 1407, then Lester will gain 14 rating points, and Charles will lose 14 rating points, as the two players had a rating difference of 463 points.

In the event of a tie game, the lower rated player will gain as many rating points as indicated in the fourth column and the higher rated player will lose that many rating points.

Spread Bonus

In addition to the Basic Change, the winner of the match also gains bonus points for the spread (i.e. the point difference in the score) of the game as shown in the following table and the loser loses that many points:

The spread bonus does NOT apply when the two players are more than 400 rating points apart.

For example: If Pierre (1234) wins against Mackenzie (1007) by a score of 416-303, then Pierre will gain 6 rating points, plus an additional 2 rating points as a spread bonus, for a gain of 8 points. Mackenzie will lose 8 points.

Newcomer Multiplier

A new player who has played fewer than 50 games at the club will see their overall rating change doubled. After the 50th game, their rating change will no longer be doubled. This effect is shown on the Ratings List, but not on the Scoreboard. For example: If Lester (944) has only played 33 total games at the club, he would be considered a newcomer. If Lester\’s overall rating change for a club session was +28, his rating gain would become +56.

Expert Cushion

An expert is a player with a club rating over 1800. An expert rated between 1800-1999 will see their overall rating change reduced by a fractional multiplier of 0.8. An expert rated higher than 2000 will see their overall rating change reduced by a fractional multiplier of 0.6. This prevents an expert\’s rating from fluctuating as much as other players. This effect is shown on the Ratings List, but not on the Scoreboard. For example: If a player, Kim, rated 1933, had an overall rating change for a club session of +15, Kim\’s rating gain would become +12.

Club Championship

Players are awarded 2 points for a win, 1 point for a loss and 1.5 points for a tie. At the end of the season, our Club Champion will be crowned!

For further information regarding the calculation of ratings and statistics, please contact the Directors.

See also:

Ratings and Statistics
Scoreboard
Season Records
Sit-Out List