This page explains how Patrick Keville (USATT# 77971)'s rating went from 1931 to 1920 at the LYTTC Friday Pro League event from 23 Oct 2020. 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.