This page explains how Keith Carson (USATT# 221111)'s rating went from 1078 to 1066 at the 2021 Arizona Open & Giant Round Robin held on 25 Sep 2021 - 26 Sep 2021. 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.