Sunday, 2 November 2014

Changes to the grading system

As from January 2015 there will be a number of changes to the calculation of ECF grades.

The ECF Grading Team has decided to address two major issues of concern:

A.   The harmful effect of incorrectly reported dates.   These occur chiefly, but not exclusively, in club championships where very often a single arbitrary date is assigned to every game in the competition.   This places undue weight on the precise dates of games played around the 30-game cut-off point.   The order in which two games were played can make a difference of 3 points or more to the player’s grade two years later.

B.   The need to indicate the strength of players as early as possible, noting that a grade for ungraded players is already visible by referring to the games listed in their opponent’s database record.

In consequence there will be three changes introduced in the January 2015 grading list:

1.   At present, category A grades are calculated by averaging the grading points from the most recent 30 games.   Starting in January the averaging will be over all games in the previous two grading periods.   This change will mean that category X will become redundant.

2.   At present, grades in categories lower than A are calculated over the most recent 30 games, assuming that the player has played more than 30 games in the last three years.   In January the calculation method will revert to the system used until January 2011.   There will no longer be a cut-off point part-way through a grading period.   Instead, the system will take as many games from each prior period as it needs in order to make 30 games, but they will use grading points for the average per game for the earliest period used.

3.   There will be a new grade category F, requiring only five games in the last 36 months (including at least one in the most recent period).   Category F grades will be published like any other grade, but they will not be used in future calculations.

A further benefit of (1) and (2) is that they are expected to reduce 'stretch' in the system.   Testing suggests that they are neither inflationary nor deflationary.

Change (3) will increase the number of players with published grades (currently less than 12,000) to an estimated 13,600 or more.   However, some concern has been expressed by congress organisers that a grade calculated from just five games may create a highly inaccurate representation of the player's ability.   This can be reflected in graded sections and grading prizes.


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