This page explains how Italo Ivaldi (USATT# 1361)'s rating went from 1622 to 1613 at the South Shore Sports/Butterfly O held on - 15 Nov 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.