Six Sigma Implementation Success Factors Across Manufacturing, Healthcare, and Services: A Large-Scale Multidisciplinary Analysis

Somkenechi Chinwe Okpala¹, Charles Chikwendu Okpala²

¹ Paediatrician, Department of Paediatrics, University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu – Nigeria.  

 ² Professor, Department of Industrial/Production Engineering, Nnamdi Azikiwe University, Awka – Nigeria. 

Abstract

This study investigates Six Sigma implementation success factors and their measurable operational and sustainability impacts across manufacturing, healthcare, and service sectors using a large-scale multidisciplinary dataset of 412 organizations over a five-year performance window. Drawing on multilevel modeling and structural equation analysis, the research identifies leadership commitment (β = 0.41, p < .001), data infrastructure maturity (β = 0.36, p < .001), sustainability alignment (β = 0.33, p < .001), and cross-functional integration (β = 0.29, p < .01) as the strongest predictors of sustained Six Sigma success across industries. Cross-sector comparisons reveal that manufacturing firms achieved the highest average cost savings per project (US$1.8 million), healthcare organizations generated the greatest waste reduction gains (27%), and service organizations realized the fastest cycle-time improvements (34%). Sustainability-aligned Six Sigma deployments produced 23–38% higher long-term ROI and up to 73% greater energy reduction compared to non-aligned initiatives, demonstrating sustainability as a performance amplifier rather than a trade-off. Methodologically, the study introduces the Multilevel Sustainability-Integrated Six Sigma Model (MS-SSM), offering a replicable framework linking critical success factors to triple-bottom-line outcomes. The findings position Six Sigma as a scalable organizational capability for operational excellence, ESG-driven sustainability transformation, and durable competitive performance across diverse institutional contexts.    

Keywords: Six Sigma, Critical success factors, Sustainability alignment, Multilevel modeling, Healthcare quality improvement, Manufacturing performance, Service operations.

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