This page explains how Rainer Eysser (USATT# 5679)'s rating went from 1680 to 1645 at the US Nationals held on - 19 Dec 1999. 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.