This page explains how Kai Zhang (USATT# 86637)'s rating went from 2624 to 2620 at the Westchester 2013 April Open held on - 28 Apr 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.