This page explains how Ying Zhang (USATT# 90711)'s rating went from 1209 to 1227 at the Westchester 2017 December Open held on 29 Dec 2017 - 30 Dec 2017. 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.