ELO Icon

ELO Rater

Rating Systems


USCF Rating System:

Details about the USCF rating system has been given by Prof. Mark E. Glickman of Boston University on his web pages at http://math.bu.edu/people/mg/uscf/rs/rs2.html

The initial 'provisional rating' period during the first 20 games is implemented as well as the rating floors as specified by USCF rules. The only deviation from the standard USCF rating system is the refusla to implement the 'event' logic.

The event logic allows the entry of many games to be processed at one time. This logic uses an averaging mechanism because the order of the games is lost in the reporting process. This averaging mechanism causes a slight loss of integrity in the final result. This loss of integrity has been deemed acceptable for the USCF because the burden of single game processing, both on the computaional resources, and on the tournament directors to provide the data, are cost prohibitive. Furthermore, one can argue that in a large group, the dynamics of the large group in a statistical sense will cause the errors to become self correcting. With a statistically small sample of players, a few dozen, which is the size of most clubs and groups, the loss of integrity of the event logic may not be self correcting. Also in a small gourp, the bourden of single entry is not too large. For these reasons, this program forces single entry fo games, providing the most acurate rating possible with small gorups.

Harkness System:

The table below shows the harkness system implemented by the program.

Opponnent
Rating
Difference
If High Wins
Add to Winner and
Deduct from Loser
If Low Wins
Add to Winner and
Deduct from Loser
If a Draw
Add to Low and
Deduct from High
0 to 2416160
25 to 4915171
50 to 7414182
75 to 9913193
100 to 12412204
125 to 14911215
150 to 17410226
175 to 1999237
200 to 2248248
225 to 2497259
250 to 27462610
275 to 29952711
300 or more42812