This page explains how Phong Qung Bui (USATT# 87937)'s rating went from 1853 to 1821 at the 2023 Butterfly Cary Cup held on 27 Apr 2023 - 30 Apr 2023. 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.