Lytham Bridge Club is preparing for the introduction of the EBU Pay To Play scheme which starts on 1st April 2010.
Here are some links to relevant information about the scheme.
The following document gives information about The National Grading Scheme (NGS)
Objectives for the NGS
The NGS is to be an EBU service which is intended to be relevant to the vast majority of the membership, and not just for the existing tournament players, i.e. it is not to be a service which would be perceived by many to be “by the elite for the elite”. Hence, the objectives for the National Grading Scheme are: To provide a fair and trustworthy measure of an individual’s current performance when playing duplicate Bridge, which: Is easy to understand. Calculates changes (both up and down) in an individual’s current standard of play. To enable new competitions to be constructed for use in Club, County and National competitions based on the current performance of individuals, through treating the measure of current performance as a “handicap”. It should be noted that the NGS is complementary to the Master Point Scheme, whose existing arrangement is unaltered by the NGS proposal. The two schemes are independent. The Master Point Scheme provides an indicator of an individual’s aggregated lifetime achievement in Bridge, whereas the NGS indicates an individual’s current playing ability based on the last 40 (or so) playing sessions.
The Basic Proposal of the NGS
The NGS proposes that: Every EBU member has a “grade” Which is an indication of that person’s current playing ability Based on his/her results over the last 1,000 boards played (in all partnerships and all competitions) The most recent playing session contributing the most to the grade, previous results having a progressively reducing significance See also “Anonymous Members and NGS Opted-Out Members”. There is a progressive sequence of 13 “grades” Named “2” (novice) to “Ace” (top expert) “Ace” being sub-divided (by suit), so as to distinguish the top experts further Indicating that an individual’s current performance lies in a band Covering an equal percentage segment (2%) of the normal distribution of Bridge skill Implying that there will be different populations of member in each grade. An individual’s grade is based on a personal “grade value” which is: A percentage (maintained to several decimal places for reasons of accuracy) Calculated based on the last 1,000 boards that the individual has played As reported to Aylesbury, i.e. it includes results from Club, County and National events Analysed in chronological sequence by date and time of play Such that older results have a progressively reducing significance (using straight line decay to zero).
The mathematics anticipates the following populations in each grade, based on an example participation of 50,000. Applicability of the NGS As well as producing a grade for an individual, grades will also be calculated on a partnership basis, thereby allowing a member to observe the grade of the various partnerships in which they play, the latter enabling them to identify the partnership in which they perform the best (or, for that matter, the worst). Also averaging the grades of the participants gives an indication of the standard of the field in that playing session. Thus, grading applies to: An individual Partnerships in as many combinations as occur Playing session and sections in Clubs, Counties and Nationally
The Operation of the NGS
The NGS is being designed to “look after itself” in a fully automatic manner. A scoring result as returned to Aylesbury contains all the information necessary and is processed on receipt by the NGS to reflect any changes to grades as soon as possible. Therefore, there is no additional work for a club to engage with the NGS. The NGS re-calculates an individual’s grade value using the results achieved by that individual in that playing session. The nature of this calculation depends on the movement which has been used. However the grade value of the individual’s partner as well of the grade values of opponents is taken into consideration. As a consequence, it is unnecessary to classify particular events by their (perceived) standard, i.e. the context (e.g. National Congress, County Event, or Club Session) in which the result was achieved is irrelevant. Note that the grade value of every participant remains the same throughout the playing session (i.e. it is not varied on a board by board basis), so the order in which the boards of the playing session are played is immaterial. The result of the analysis of the whole the playing session is reflected in an alteration to an individual’s grade value. If the grade value crosses a band boundary, then the player’s grade will change. An individual can observe the information pertaining to his/her grade by way of the membership record. Grades will be public and accessible by the use of an individual’s EBU number (much like today’s Master Point information) or by name. However, other information will be private and will include: Grades in various partnerships, Grade value, Position in NGS (or Grade), Catalogue of contributing playing sessions and Grade history. Additional Information Initialisation and Evolution of an Individual’s Grade: In order to preserve its mathematical and statistical integrity, any new joiner to the NGS commences with a grade of “8”. An individual’s grade then “evolves” in accordance with their performance in practice at table. Experience with existing rating systems has shown that an individual’s grade broadly stabilises after the play of about 600 boards (i.e. approximately 24 playing sessions). The more partners a player has, and the more clubs they play in, the more representative the grading. For many cases, a good first approximation occurs after only 300 boards. Accordingly, the NGS does not propose to indicate an individual’s grade until 12 playing sessions (i.e. about 300 boards) have been played. This mechanism will be applied to existing members when the NGS is introduced, i.e. there will not be any subjective assessment of an individual’s grade, for example, based on his/her Master Point Rank. Types of Duplicate Bridge game contributing to a Grade: The initial phase will use results from all, except very rare types of, Pairs events and a further phase will also use results from Teams and Individual events. Currency of an Individual’s Grade: To have a current grade an individual must have had at least 12 playing sessions within the Playing Year. This implies that an individual cannot retain their grade by discontinuing playing. Individuals whose grade loses currency will be so marked. Board Inclusion: All boards of a playing session will be included, even when the score of that board has been adjusted, e.g. for a revoke or a mis-boarding, such incidents being considered to be part of the game. Events Scored Twice: Only the first (club) instance of the scoring result will be included from those events, such as Simultaneous Pairs, which are multiply scored. Anonymous Members and NGS Opted-Out Members: An “anonymous” EBU member will not be able to see his/her grade. Other EBU members can choose to “opt-out” of the NGS altogether and this will be marked in their membership record, which will not include their grade. However, note that both these categories of individual will actually be graded, because their standard of play has an influence on the grades of their partners and/or their opponents. In addition, there will be an option for up to one (but only one) person to opt-out on a playing session basis. This accommodates situations in which there are “hosting” or “mentoring” players involved in the playing session. The option does not have to be used and it is at the discretion of the organiser of the playing session to determine which player may use this capability.
Derivation of a Handicap from a Grade: The NGS lends itself well for use as a handicap. For example in Pairs events each player’s handicap could be approximated by a simple conversion scale of -6 for a grade of "Ace" to +6 for a grade of "2". A partnership’s handicap is the sum of the two player’s handicaps and this is the amount by which the event’s percentage score is adjusted in determining the handicapped result. This approximation might be acceptable for “fun” events (such as a club party), but does entail a potential grade value error for a pair of up to 2%. Therefore, for more “serious” events in which handicaps are employed, it would be necessary to use a more accurate conversion of the grade values. Prizes, Publicity and New Club-based Competitions: These considerations are all outside the remit of the NGS. However, it is possible to devise annual awards based on the NGS (the corollary to those currently provided in the Master Point Scheme); although with a large number of grades these may not be for each grade. English Bridge will contain grade information, in particular a list of the top players which is likely to be of interest to many, but probably not changes in the grades of individuals. New club-based competitions, e.g. using (rough or precise) handicaps, are enabled through the NGS. Health warning: Note that “Grades can go down as well as up”. It is suggested that this appears on every pack Hope warning: Grades won’t always go down. If you have a really good playing session your grade just might go up ☺ |