This page explains how Wally Barber (USATT# 62880)'s rating went from 611 to 604 at the 2013 Arizona Open held on - 17 Feb 2013. 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.