This page explains how Wei Qin (USATT# 215793)'s rating went from 838 to 812 at the ICC - Sunday Beginners League event from 3 Oct 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.