This page explains how Joseph S. Helfand (USATT# 6564)'s rating went from 1491 to 1463 at the May Open held on - 26 May 2007. 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.