This page explains how Hanson Qin (USATT# 81606)'s rating went from 458 to 420 at the ICC - Entry Level League event from 26 Oct 2010. 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.