LEADER BOARD

ELO | Annual | ||

Player | Exp | Rating | Points Race |

Tom Meyer | 52 | 1518.66 | 19.5 |

Jay Karns | 69 | 1506.82 | 17 |

Jim Sisti | 69 | 1511.85 | 16 |

Sandy Sisti | 55 | 1487.87 | 11.5 |

Ross Gordon | 15 | 1526.77 | 10 |

Al Theriault | 34 | 1497.29 | 8 |

Al Cantito | 67 | 1489.48 | 7.5 |

Jim Stutz | 21 | 1511.00 | 6 |

Ed Corey | 33 | 1510.56 | 5.75 |

Bill Porter | 16 | 1500.01 | 2 |

Dave Mirto | 11 | 1491.44 | 1 |

Rob Roy | 8 | 1484.85 | 0 |

Andy Fazekas | 10 | 1482.17 | 0 |

Frank V. | 12 | 1481.23 | 0 |

Updated 3/24/17

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.