This page explains how Zack Guido (USATT# 214914)'s rating went from 1691 to 1564 at the Westchester December 2019 Open held on 28 Dec 2019 - 29 Dec 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.