This page explains how Dave Williams (USATT# 11140)'s rating went from 1589 to 1578 at the Maryland Medallion Championshi held on - 12 Jun 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.