This page explains how Joseph S. Helfand (USATT# 6564)'s rating went from 1513 to 1506 at the December Open held on - 11 Dec 2010. 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.