This page explains how Bill Z Zhang (USATT# 84158)'s rating went from 1521 to 1499 at the September Newgy Giant Round Robin held on - 14 Sep 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.