This page explains how Mark Johnson (USATT# 26863)'s rating went from 1859 to 1870 at the ICC Juniors and Adults League event from 29 Sep 2008. 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.