This page explains how Changping Duan (USATT# 49379)'s rating went from 2027 to 1993 at the Maryland State Championships held on 10 Jun 2017 - 11 Jun 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.