Evaluating Lean Six Sigma's Impact on Operational Efficiency in Small and Medium-Sized Manufacturing Enterprises: A Systematic Review

The increasing demand for operational efficiency in small and medium-sized manufacturing enterprises (SMEs) has sparked interest in Lean Six Sigma (LSS) methodologies. LSS integrates Lean’s waste elimination focus with Six Sigma’s variability reduction, offering a comprehensive framework for process improvement. Despite its potential, SMEs face unique challenges in implementing LSS, such as financial limitations and resistance to change. This systematic review evaluates the application of LSS in SMEs, analyzing its impact on operational, financial, and quality performance across different industries and geographical regions. The study identifies key success factors, barriers, and research gaps while proposing regression models to predict financial gains associated with LSS adoption. The review followed PRISMA guidelines, sourcing literature from SCOPUS, Web of Science, and Google Scholar published between 2014 and 2024. The inclusion criteria targeted studies involving LSS implementation in manufacturing SMEs. Data extraction included study characteristics, methodologies, and outcomes. A risk of bias assessment was conducted using the Newcastle-Ottawa Scale. The synthesis involved descriptive statistics, effect measures, and sensitivity analyses. Out of 150 initially identified studies, 109 met the inclusion criteria. The findings demonstrate that LSS implementation significantly improves operational performance, with 77.98% of studies showing reductions in cycle time and defect rates. Financial outcomes, including cost savings and ROI, showed moderate to large effects, with 63.58% of the reviewed studies reporting cost reductions. Quality improvements were noted across studies, particularly in First Pass Yield, with 67% of studies demonstrating enhanced quality metrics. The geographic distribution indicated strong research activity in India (23.85%), the United States (6.42%), and Europe (5.50%). Both developed (46.79%) and developing (45.87%) economies contributed extensively. Key barriers included resource constraints (reported in 45% of studies) and resistance to change (noted in 31%). LSS offers substantial benefits for SMEs, driving process efficiency, cost reduction, and quality improvements. However, challenges such as limited resources and organizational resistance must be addressed for successful adoption. This review provides insights into best practices, highlights research gaps, and suggests areas for future investigation, emphasizing the need for customized LSS strategies tailored to the unique contexts of SMEs.