This page explains how Michael Zhang (USATT# 89100)'s rating went from 1921 to 1872 at the LYTTC Friday Pro League event from 13 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.