This page explains how Sean Masterson (USATT# 77070)'s rating went from 1271 to 1265 at the 2009 Northridge Open held on - 20 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.