This page explains how Jean William Barthold (USATT# 71069)'s rating went from 1559 to 1523 at the Carmel Barrau 2021 December BTTC Open Tournament held on 10 Dec 2021 - 12 Dec 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.