This page explains how Ann-ping Shangguan (USATT# 97927)'s rating went from 2179 to 2155 at the LYTTC Friday Pro League event from 27 Sep 2019. 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.