This page explains how Mark Kasdorf (USATT# 26450)'s rating went from 909 to 900 at the Mohawk Valley TTC League event from 19 Jan 2004. 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.