This page explains how Charles O Olisa (USATT# 97816)'s rating went from 1922 to 1915 at the 2021 US National TT Championships Southcentral Regional Qualifier held on 28 May 2021 - 30 May 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.