This page explains how Andrew Zhou (USATT# 202548)'s rating went from 2006 to 1958 at the OCTTA Butterfly August 2021 Open held on 21 Aug 2021 - 21 Aug 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.