Driving synergy: can TOC, lean, and six sigma integration work without flexibility?

Abstract

This study aims to empirically assess the combined impact of Theory of Constraints (TOC), Lean Manufacturing (LM), and Six Sigma (SS) – collectively known as TLS – on business performance in Indian manufacturing companies. Importantly, it investigates the role of manufacturing flexibility in influencing this relationship. Using a structured survey, data were collected from a diverse sample of Indian manufacturing companies. The study employs statistical techniques including Partial Least Square-Structural Equation Modelling (PLS-SEM) for model measurement, multiple regression analysis to test the influence of TLS on various performance metrics and hierarchical regression analysis to explore the moderating role of manufacturing flexibility. The results indicate that the implementation of TLS significantly improves business performance across several dimensions, including productivity, quality, and operational efficiency. Companies that have effectively integrated TLS into their operations report greater performance gains compared to those using individual or partial methodologies. Moreover, manufacturing flexibility is found to strengthen the relationship between TLS implementation and business performance, suggesting that companies with higher flexibility can better leverage TLS for enhanced operational outcomes. This study is among the first to empirically validate the impact of TLS integration on business performance in the context of Indian manufacturing. It also contributes to the existing literature by exploring the role of manufacturing flexibility, a factor that has received limited attention in previous research. The findings provide a robust framework for manufacturing companies seeking to implement TLS and highlight the strategic importance of flexibility in achieving operational excellence.