This page explains how William Ding (USATT# 220335)'s rating went from 1570 to 1566 at the Westchester 2021 July Open held on 24 Jul 2021 - 25 Jul 2021. 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.