Extending OEE to OEE–OS: Integrating Obsolescence and Shortages into Equipment Performance Measurement
Obsolescence and shortages in manufacturing enterprises are critical challenges that directly affect operational efficiency, equipment reliability, and production continuity. However, manufacturing enterprises often lack holistic operational strategies that comprehensively consider and quantify these factors while maintaining competitiveness. In particular, Key Performance Indicators (KPIs) to measure the impact of obsolescence and shortages on equipment effectiveness and to facilitate root cause analysis at the operational level are missing. Currently, the management of obsolescence and supply shortages is often addressed in a reactive or theoretical way, whereas maximizing equipment performance remains the primary focus. To transition towards a more resilient and robust manufacturing system, these factors should be systematically integrated, ensuring that operational efficiency is not compromised by aging equipment or parts shortages. To pursue this line of research in operations management, this paper introduces a conceptual approach incorporating obsolescence and shortage factors into equipment performance assessment. The approach is based on a causally-structured framework supported by a triangulation of literature review, causal modeling, and qualitative industrial feedback. It supports decision-making at both strategic and operational levels and lays the foundation for the development of a novel KPI schema, in particular focusing on the extension of OEE towards Overall Equipment Effectiveness for Obsolescence & Shortages (OEE-OS). The approach is illustrated through a PLC-based industrial case study highlighting the gap between classical OEE and OEE–OS.