This page explains how Zack Guido (USATT# 214914)'s rating went from 1899 to 1887 at the 2023 Butterfly Puerto Rico Teams Open held on 31 Mar 2023 - 2 Apr 2023. 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.