FIBS Rating Formula*


These are the formulas used to determine the ratings of a player:


Let's say that two players P1 and P2 were playing a n-point match. The ratings of the players are r1 for P1 and r2 for P2 .


Let D = abs(r1-r2) (rating difference)

Let P_upset = 1/(10^(D*sqrt(n)/2000)+1) (probability that underdog wins).

Let P=1-P_upset if the underdog wins and P=P_upset if the favorite wins.


For the winner:

Let K = max ( 1 , -experience/400+2 )

The rating change is: 4*K*sqrt(n)*P


For the loser:

Let K = max ( 1 , -experience/400+2 )

The rating change is: -4*K*sqrt(n)*P


The 'experience' of a player is the sum of the lengths of all matches a player has finished. Every player starts with a rating of 1500 and an experience of 0.


*Thanks to FIBS (First Internet Backgammon Server) for providing the rating formula as part of their HELP menu.


Player Experience ELO Rating 2019 Points Race
Al Cantito 1567 1687.62 61.5
Andy Fazekas 667 1534.85 44.5
Ed Corey 1093 1447.82 37.75
Ray Nilson 841 1464.77 35
Jim Sisti 1464 1533.57 34.75
Jerry Shea 1037 1527.04 34
Sandy Sisti 1287 1353.24 33.5
Jay Karns 904 1566.98 30
Derek Meredith 21 1507.29 7.5
Frank DiMaggio 24 1516.94 6
Adrian Costa 362 1410.00 6
Al Theriault 257 1483.51 3
Bill Porter 470 1618.63 2
Jim Stutz 188 1550.02 1

Updated 3/15/19


Annual Points Race Accrual Methodology


For each tournament event, Points are awarded to players as follows:


1.  A player receives 1 Point for each match they win and for every meetup they attend.


2.  Tournament Points are established based on the number of event participants and distributed thus:


A.  1st Place receives an amount equal to the total number of participants


B.  2nd Place receives an amount equal to one-half the total number of participants


C.  3rd Place (Optional) receives an amount equal to one-quarter the total number of participants


All tournament event points awarded to a player are added to their annual cumulative total.