This page explains how Olaf Surmann (USATT# 81607)'s rating went from 2192 to 2186 at the 2018 ICC Butterfly America Open held on 7 Dec 2018 - 9 Dec 2018. 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.