This page explains how Michael Zhang (USATT# 89100)'s rating went from 1924 to 1921 at the LYTTC Friday Pro League event from 5 Dec 2015. 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.