Introduction

The current linear rating system has been used since the beginning of the PSA rankings. Since then, Pakistan’s Scrabble community has grown considerably. As more players compete, a zero-sum system, where every rating point gained must be taken from another player, becomes increasingly restrictive because the population is competing for a limited pool of points.

Key Differences

The WESPA RJR rating system is non-zero-sum, meaning that one player’s rating gain does not have to equal the opponent’s rating loss. Rating differences represent expected winning chances: a 100-point advantage corresponds to approximately a 60%–40% expectation, while a 200-point advantage corresponds to approximately 69.5%–30.5%.

Player Uncertainty: Rating Deviation

The RJR System also measures the level of uncertainty in each player’s rating. Players who have been inactive for longer accumulate greater uncertainty and experience larger rating movements when they return. Active players have more stable ratings. The size of rating changes also varies by rating tier, so the same result may affect players at different rating levels differently.

Transition

Established players who have competed since 2019 received an initial increase of 450 points to prepare the rankings for the new system. Players with fewer than 50 rated games remain provisional and received a smaller increase.

The new ratings will take effect after the 38th Pakistan Scrabble Championship.