This page explains how Ying Zhang (USATT# 90711)'s rating went from 667 to 649 at the Westchester 2013 July Open held on - 21 Jul 2013. 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.