This page explains how Sebastian DeFrancesco (USATT# 38930)'s rating went from 691 to 641 at the US Nationals held on 14 Dec 2015 - 18 Dec 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.