This page explains how John Karp (USATT# 15756)'s rating went from 1643 to 1639 at the Atlanta Giant RR held on - 3 Nov 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.