This page explains how Haoran Guan (USATT# 211903)'s rating went from 1680 to 1640 at the Westchester 2021 June Open held on 26 Jun 2021 - 27 Jun 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.