This page explains how Mark Johnson (USATT# 26863)'s rating went from 1640 to 1609 at the SVTTC Sunday U2000 event from 11 May 2014. 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.