This document discusses a study that investigates using Overall Resource Effectiveness (ORE) to evaluate manufacturing systems performance. ORE expands on the traditional Overall Equipment Effectiveness (OEE) metric to include additional factors like material availability, manpower availability, and changeover efficiency. The study presents ORE as a way to identify losses across the entire manufacturing system and initiate improvements. It also reviews previous literature on using OEE and related metrics to measure equipment performance and the benefits of total productive maintenance approaches. The objective is to contribute to understanding of how to holistically evaluate manufacturing systems and processes.