This page explains how Mark Shapiro (USATT# 61560)'s rating went from 1818 to 1781 at the John Jorgensen League event from 9 Oct 2003. 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.