Bob Fearn, is the author of Compass scoring which is the engine powering X-Clubs and, for the last four years, the NZ-Wide Babich Simultaneous Pairs. In 2018 Bob took an interest in scoping out a National Grading System (NGS) for use in New Zealand. An NZB NGS would open up a whole new dimension to our game - handicaps. Bridge players can now go out to beat their handicap not their playmates. This challenge is now available for all players of X-Club deals.
Bob completed this massive project using the X-Clubs data-set as a basis. In effect all players of X-Club hands will earn an X-Clubs rating. It is called XG . This XG system opens the door for NZ bridge to provide large-scale handicapped results.
Calculating the XG involves a huge amount of data crunching which Bob does weekly so that any score changes get incorporated. The method closely parallels the EBU model and involves consideration of your XG, your partner's XG, and the combined XG of your opponents. It builds up over the most recent 2000 boards before old scores begin dropping off. A minimum of 300 boards - about 12 sessions - need to be played before an XG starts to settle down.
The three categories of XG Status U, E, M are Unpublished (played < 150 boards), Evolving (played between 150 and 1000 boards) and Mature (played > 1000 boards). This is because it takes a while for the XG's to settle down. Michael Neels from Cambridge has worked on this with Bob Fearn.
The XG is like a typical club handicap. “Average” players will have an XG of around 50%, and more experienced players will to have higher XGs, say 55% to 70%. New XGs are recalculated after every session played and is based on the players existing XG, their partners XG, the average XG of their opponents, and each pair’s actual session score. The recalculated XG is a weighted average of the session score for the last 2000 deals played, with recent results being given a higher weighting than older results.
Handicapping at Taupo
The match committee has put in place some handicap sessions for 2020. These will be based on your XG grade.
Your XG grade comes from X-club and for each player a corresponding value is calculated and entered into our scoring program database. This can be done weekly, monthly or at the start of a new competition.
Martin Oysten from BridgeNZ has customized scorer to allow the import of this or other type of data from csv files.
When scoring a particular session the program will “normalize” these handicaps to match the current session. In other words the handicaps will average zero for each session.
Handicapping is Dynamic In other words you can expect variation week to week, because of the “normalizing” and the new XG grading from X-Club
How to find your XG Rating (updated weekly)
To find your XG Rating you need to go to X-Club
Go to Sunday at the bottom of the page. Three reports appear here.
Click on the last one XG Rating/ Ladder. Does take a little time to Load
Use “Ctrl F” and enter your name in the box. You can click on Headings at top of the report to re-arrange.
or on a tablet (android) instead of "Ctrl F", touch the three vertical dots and select 'Find in Page" and enter your name.