This page explains how Mohammed Yasin Musthafa (USATT# 219888)'s rating went from 80 to 78 at the ICC - Sunday Beginners League event from 1 Sep 2019. 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.