This page explains how Qi Guo (USATT# 80876)'s rating went from 1939 to 1937 at the LYTTC Friday Pro League event from 16 Nov 2014. 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.