This page explains how Toon Siong Mao (USATT# 55611)'s rating went from 2046 to 2038 at the San Francisco Summer Open held on - 22 Aug 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.