This page explains how Xujing Zhang (USATT# 199299)'s rating went from 648 to 631 at the ICC - Sunday Beginners League event from 17 Apr 2016. 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.