This page explains how Raymond F. Chen (USATT# 4809)'s rating went from 1589 to 1582 at the Butterflly MDTTC September Ope held on - 13 Sep 2009. 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.