This page explains how David J. Roddick (USATT# 70987)'s rating went from 948 to 929 at the 2009 Butterfly Cary Cup Champi held on - 22 Mar 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.