This page explains how Bosman Botha (USATT# 219904)'s rating went from 42 to 38 at the WCTTA Saturday League event from 9 Dec 2017. 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.