This page explains how Ali Shafai (USATT# 52354)'s rating went from 1649 to 1620 at the ICC - Advanced League event from 13 Jul 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.