This page explains how Jason M Liu (USATT# 263284)'s rating went from 641 to 630 at the 2019 US Nationals held on 30 Jun 2019 - 5 Jul 2019. 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.