This page explains how Charlie Lapkoff (USATT# 222818)'s rating went from 1537 to 1518 at the MDTTC Tuesday/Friday League event from 18 Feb 2020. 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.