This page explains how Changbo Lu (USATT# 202365)'s rating went from 2242 to 2221 at the 2021 Butterfly Invitational held on 15 Apr 2021 - 18 Apr 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.