are Processed

The new ladder is derived from the previous one in the following steps:

- Unreported scores are recorded as zero, except in case of reported default.
- Players with zero or one matches were not moved up or down, but were dropped by default. Their played matches are not counted.
- The two highest ranked players in a box are lifted to a point just above the middle player in the next higher box.
- The two lowest ranked players in a box are dropped to a point just below the middle player in the next lower box.
- In case of two players tying, the stronger player is taken as the one who beat the other in their one-on-one match.
- A player who dominates their box has the option of moving an extra box or two higher.
- Players who played one or no matches are moved to the Ghost Ladder.
- New players are seeded in.

The computation used to work up the March and April ladders was the following.

Unplayed matches are ignored. There are no defaults. If you beat a player rated better
than yourself, it affects both your ratings more than if you beat a worse-rated
player. If Lee Beachill beats you, it doesn't change the world much. But if you
were to beat Lee Beachill, champagne's on the CRFC.

Let HIGHER be the higher-rated player.

Let LOWER be the lower-rated player.

Let DIFF be the difference in ratings, i.e. rating(HIGHER) - rating(LOWER).

Let PERC be the percentage of games won by the winner. (3-0 => 100%; 3-1 => 75%
etc.)

Let STEP be the average difference in ratings between two adjacent players in
the ladder.

Let ADJ_W be the amount added to the winner's rating.

Let ADJ_L be the amount subtracted from the loser's rating.

If HIGHER beats LOWER:

ADJ_W = PERC * STEP / (1.0 + DIFF/STEP)

ADJ_L = ADJ_W

If LOWER beats HIGHER:

ADJ_W = 2.0 * PERC * (STEP + DIFF)

ADJ_L = 0.5 * PERC * (STEP + DIFF)

The gory details of what Harold does every month is
here.

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