This page explains how Lynn Brown (USATT# 1171153)'s rating went from 647 to 647 at the Butterfly 2021 September BTTC Open held on 24 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.