Why a rating system?
Many Scrabble clubs – including ours – use a numerical rating system to represent the playing strength of their members. In our case we use ratings to aid in pairing up players of similar strength and to divide our internal tournaments into divisions. It also gives players a chance to track their improvement as time goes by.
What system do we use?
At the Montreal Scrabble Club, we use a rating system designed by Stephen Fisher. As far as I know, we are the only club using this rating system. It differs from the NASPA rating system in that point spread is taken into account. The more you beat someone by, the more rating points you earn. It also has the unusual feature that if opponents are sufficiently mismatched the loser can still gain rating points if the game is close enough. Similarly the winner can lose points.
The way it was presented to me is something like this: Generally, the points gained by one player are lost by the other (I’ll explain the exceptions below). For winning a game you get a basic 10 points. However, each 50 points you beat someone by earn you an extra rating point, to a maximum of four. Points are also awarded depending on the difference in your ratings. If you are the ‘underdog’ you get an extra point if you’re behind by 400 to 499 rating points, two if you’re behind by 500 to 599, and so on up to a maximum of 6 points. However, if you are the favourite by more than 100 points you get docked 2 points or more depending on the extent of your lead in the ratings. If you’re ahead by more than 800 points you actually lose points for winning, unless you make up for it in spread points. If you tie, the points are the ‘hundreds column’ of the ratings difference.
It sounds complicated in words! It was presented to me as two tables which I don’t have anymore, but my spreadsheet uses a single combined table as follows:
|Winner’s Rating minus Loser’s Rating||Points awarded before spread adjustment|
No-one’s rating is allowed to fall below 1000. Ratings below 1000 are automatically set to 1000.
Often players take on two opponents at once to prevent someone from sitting out a game. If such a player loses rating points the amount is halved. The opponent gets full credit for the win.
Sally (rated 1710) beats John (rated 1200) by 75 points. She gets 2 rating points for the win, plus 1 for the spread. John accordingly loses 3 rating points.
If John beats Sally by 75 points, the ratings difference is –510, so he gets 12 rating points for the win, plus 1 for the spread. Sally accordingly loses 13 rating points.
Spot (rated 2500) plays John and Sally at the same time. He beats John by 10 points. John gets 2 points for coming so close, Spot only loses 1 point because of the double game. Spot loses to Sally by 10 points. Sally gets 14 points and Spot loses only 7 because of the double game.
Sally and John tie. John gets 5 points and Sally loses 5 points.