This page explains how David R. Zapatka (USATT# 11394)'s rating went from 1537 to 1557 at the Serve Curve and Rally Open held on - 17 Sep 2011. 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.