This page explains how THOMAS YOST (USATT# 14987)'s rating went from 1596 to 1630 at the Portsmoutn Open Invitational held on - 21 Mar 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.