This page explains how James Petrie (USATT# 55556)'s rating went from 1381 to 1356 at the Tucson Open held on - 29 Jul 2007. 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.