LEADER BOARD

ELO | Annual | ||

Player | Exp | Rating | Points Race |

Tom Meyer | 101 | 1538.55 | 35.5 |

Jay Karns | 86 | 1532.59 | 26 |

Jim Sisti | 111 | 1507.29 | 25 |

Sandy Sisti | 96 | 1469.47 | 14.5 |

Al Cantito | 84 | 1495.60 | 13.5 |

Al Theriault | 50 | 1510.61 | 13 |

Mark Denihan | 17 | 1528.48 | 11 |

Ross Gordon | 15 | 1526.77 | 10 |

Ed Corey | 68 | 1468.94 | 6.75 |

Jim Stutz | 21 | 1511.00 | 6 |

Andy Fazekas | 30 | 1500.55 | 4.75 |

Bill Porter | 16 | 1500.01 | 2 |

Dave Mirto | 21 | 1475.13 | 1 |

Frank V | 37 | 1457.21 | 1 |

Rob Roy | 23 | 1477.80 | 1 |

Updated 4/21/17

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.