This page explains how Henry E. Tiedeberg (USATT# 18820)'s rating went from 696 to 686 at the Butterfly/PTTC June Open held on - 19 Jun 1999. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.