The SCBA Ratings page is live! Thus far, only matchpoint pairs games are rated, from 2023 onwards. Most of the development was done in a week with the help of ChatGPT and Claude. Why 2023? Given that SCBA re-opened in May 2022 after COVID-19 restrictions were eased, 2023 seems like a good starting point when most people returned to weekly games. How is this done? Ratings are implemented using OpenSkill, using Plackett-Luce based on rankings. ...
Point vs Interval Estimates One issue with the Elo system as previously raised is how it doesn’t give any information about the uncertainty of the estimate. The Glicko system is an attempt to encompass this information additionally. Think about this: If a player has played 3 games: win against a player rated 1500, lose against a player rated 1450 and win against a player rated 1200, how confident are we in the derived rating? On the other hand, if a player has played 50 games, and has won 35 games against opponents rated 2000 and below, drew 5 games against opponents rated 2000-2050 and lost the remaining 10 games versus opponents rated above 2050, we can be fairly certain that his rating is somewhere between 2000-2050. ...
Introduction This is going to be a new series on rating systems, which is a vastly underrated (pun intended) area of statistics and data science. Rating systems has actually been a part of my life (and probably yours), from early days in chess and then games with matchmaking like CS:GO and Valorant, to now thinking if contract bridge should also have one. Historical Context Having been around for centuries, chess is a game which people have wasted much time on arguing/debating who is the best player. It’s probably slightly surprising then that the first modern rating systems only appeared around or after the end of World War 2. The first systems (Ingo and Harkness) were quite simple and used the idea of the average rating of opponents with adjustments for the results. ...