This page explains how Donald C. Hayden (USATT# 51994)'s rating went from 1585 to 1580 at the Davison December Open held on - 15 Dec 2001. 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.