This page explains how Walter Witkowski (USATT# 21983)'s rating went from 1237 to 1222 at the 2006 Berkeley Open held on - 3 Sep 2006. 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.