Ratings documentation

General

To keep the rating list up to date, several people are involved:
  • The rating list is maintained by a team of contributors lead by Jan Ramon. Email can be sent to rating at gofed dot be (but use text files, no MsWord files please).
  • The rating commission decides on
    • the general rules used to calculate the ratings
    • the individual requests for exceptions to the rules.
    In some years, no rating commission is active, especially when the number of tasks is limited. In that case, the technical team applies a set of common practices and the board decides on more unusual or exceptional cases.
  • The club secretaries
    • report the results of club games in a correct format (see below)
    • check the correctness of the rating list
    • inform the rating team when a new player joins to provide an initial rating
  • The organisers of tournaments should send the results in a suitable format (see below).
  • Players participating in tournaments outside Belgium can send the name of the tournament if the results can be found on the web (especially the EGD), or send the results otherwise.
To structure information flow, the following procedure is used:
  1. The club secretary sends the names of the new members and an initial guess of their strength to the treasurer
  2. The club secretary sends this information to the rating list maintainer too (if using email, use 'cc' so we can see that everyone got the needed information).
  3. Intermediate rating lists are published on the web. For ratings (e.g. to determine handicaps in interclub games and for initial seeding in the belgian championship preliminary round), always the most recent list is used. If someone notices an error in a list, he can inform the rating list maintainer.
  4. Before publication in Belgo, the rating list maintainer sends a rating list to the treasurer for checking. If (1) and (2) went ok, then normally only non-members should be deleted. (Note: this rule isn't relevant anymore as not all years a Belgo is published. One can now consider the list of the website as the official list)
  5. The rating list maintainer can also send a copy to the club secretaries for checking.
    • The club secretary can then send requests for manual changes if some rating does not agree with actual strength (see below).
    • Membership errors in the rating list can be reported to the treasurer by the club secretary after checking that the player name in game results properly matches the member name reported to the membership database.
    It is important that players, organisers and club secretaries report results for the rating system to work. We hope that players will regularly check the rating list which contains also full detail of all their games and will report mistakes. One of the specific features of the Belgian system is that it allows to enter club games (i.e., results of less formal games between club members if they both agree in advance that the game is taken into account), this helps the ratings to evolve more smoothly with the changing rating of progressing players.

    The ratings

    How to submit results

    Always write the name of players as LastName FirstName, e.g.
    Bogaerts Jan
    
    Accents (éèëü...) are discarded and the system is case insensitive. Also the system makes no difference between Van Der Steen and Vandersteen.

    Ranks are represented by a number and k or d. e.g. 3k means 3 kyu and 2d means 2 dan.

    Tournaments

    We recommend that you use MacMahon by Ch.Gerlach. Just send the .TUR file and the "wall-list for the rating program" export you can make with the program. If you prefer to do things manually, follow this example:
    1  Qi Chen   3D BE 			15	9+	2+	4+	3+	5+	5
    2  Bogaerts Jan  3D BE 			14	12+	1-	6+	7+	4+	4	66
    3  Frehe Renee  3D NL			14	10+	5+	8+	1-	9+	4	64
    4  Kok Rob  3D NL			13	6+	15+	1-	8+	2-	3	65
    5  Van der Kroght Harry 1D NL		13	16+	3-	11+	17+	1-	3	63
    6  Wong Chi-Yiu 2D BE			13	4-	12+	2-	15+	8+	3	62
    
    So there is one player per line. Each line consists of field separated by spaces. The fields are:
    • Place in the tournament
    • LastName FirstName
    • Rank
    • Country (BE or BEL for Belgian players !)
    • Info (in this case macmahon score)
    • Results for every round. For handicap games write 2+/b4 if this player played black and received 4 stones. His opponent will have 10-/w4

    Club Games

    Use a text file with one game per line. Each line has 4 items seperated by ',':
    <Black>,<White>,<Handicap>,<Result>
    
    Handicap is one digit 0..9 and Result is B for Black wins and W for White wins. Player names may be followed by (rank), which will be used when the player is not a member. E.g.
    Ramon Jan,Lazarev Alexei (6d),4,W
    
    is a handicap game between a Belgian player and a Russian 6 dan, with 4 handicap, won by white.

    How ratings are computed

    Ratings

    Up to May 2001, a rather complicated formula was used to compute ratings. In its meeting of May 2001, the rating commission decided to simplify the formula to make it mathematically better and more understandable. Since June 2001, a new formula is used. It was originally based on the EGF ratings model at that time. Since then, several modifications have been made, e.g., to avoid punishing white in handicap games against improving black players, to alloax games on smaller board sizes, etc. We may not have followed all EGF modifications made over that time.

    Grades

    Ratings between 100(d-1) and 100d (d>=1) correspond to a grade of d dan. E.g. and average 3 dan has a rating of 250. Ratings between -100k and -100(k-1) (k>=1) correspond to a grade of k kyu. E.g. and average 10 kyu has a rating of -950.

    As soon as a player obtains a rating above the maximum rating for his grade, he is promoted. As soon as a player drops 100 below the minimum rating for his grade, he is demoted. E.g. a player increasing from 95 to 101 points is promoted to 2 dan. A 5 kyu player dropping from -490 to -510 remains 5 kyu. If his rating decreases further to -601, he becomes 6 kyu.

    Ratings are always computed for a complete event. A 1 dan player with rating 99 winning first 2 games and losing then 3 games in a tournament, ending up at 90, remains 1 dan even if he would have a 2 dan rating after the first day of the tournament.

    Corrections to grades are possible if new information is added. E.g. suppose a player is -510. He plays a tournament on May 1st and on May 10th. Suppose the organiser of the first tournament reports the results late. As a result of the tournament of May 10th, the player increases to -490, becoming 5 kyu. If later the information of the first tournament is added, both tournaments are recalculated. If this player appears to have lost 50 rating points at May 1st, and ends up at -525 after May 10th, he remains 6kyu.

    Manual Changes

    Players that didn't play or report results for some time can have a strength significantly different from what is in the rating list.

    Players stronger than 6kyu should motivate any request for manual change of their strength (reporting results in recent tournaments etc.). The request will be submitted to the rating commission.

    For players weaker than 6 kyu, the club secretary can propose a new rank if the new rank differs at least 2 grades from what is in the rating list.

    If both the club secretary and the player fail to report deviations of actual strength from the ratings, the rating commission may decide to manually change ratings based on tournament results. This includes but is not limited to cases where players perform 0/5, 4/5 or 5/5 or where kyu players register for a tournament with a different rank than the official one (which may be interpreted as a self-promotion) and score at least 3/5. It should be noted however, that dan players are not allowed to register for tournaments with a different rank, and that kyu players should be very careful in doing so. In any case, requesting a change is preferred rather than registering for a tournament with another rank.

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