This page explains how Kwing Yiu Lau (USATT# 4097)'s rating went from 2220 to 2159 at the MATTBC event from 14 Nov 2013. 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.