This page explains how William Horton (USATT# 91917)'s rating went from 1939 to 1942 at the 2015 Butterfly Atlanta Spring Open held on - 7 Feb 2015. 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.