This page explains how Davina Isenberg (USATT# 264091)'s rating went from 1215 to 1206 at the TT&M Friday Night Butterfly League event from 15 Mar 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.