Team Tie Break

Performance Index

Weighted sum of the total game points and the team’s Solkoff (see description below). It takes a weighted sum of the Solkoff and Game Points, with the weight on the Solkoff becoming higher as the number of rounds increases. It is based upon the following calculation: suppose a team scores S (out of G games) against an opponent who scores W match points in R rounds. Assign to this opponent a base performance value of 100+(W/R-1/2)(50+10R). (This is roughly 1/10 of the typical “rating” for such a performance if all teams had a prior rating of 1000 - we divide the “rating” calculations by 10 to give it a scale more like other tie breakers, and to avoid confusion with the actual ratings). Add to this (S/G-1/2)*80 to get the performance index for this match. Take the average of these across all of the team’s matches. (Unplayed rounds are treated as 0 scores against an opponent scoring 0, as they are in the other tie breakers). Since the sum of W’s is the Solkoff and the sum of S’s is Game Points, the result will be a weighted sum of Solkoff and Game Points. Unlike the USAT tie break, all games are equally valuable. It tends to rank teams pretty similarly to the USAT, but seems more likely than the USAT to place highly teams which lose to the top teams over those which lose to lower scoring teams.

US Amateur Teams

The USAT takes the sum of opponent’s matches won x points scored against that opponent (WinTD actually produces 2 x this definition to keep things at one decimal).