From Kaizen to sustainability: How operational lean tools drive the Triple Bottom Line

The manufacturing industry seeks to achieve operational efficiency and sustainability through lean manufacturing; however, the literature has not fully established their relationship, as prior studies have examined them in isolation and have not modeled Kaizen (KAI) as a philosophical driver that governs another Operational Lean Tool (OLT). This study proposes a structural equation model (SEM) assuming KAI as an umbrella that enforces three OLTs, namely 5S, Gemba Walking (GEM), and Muda (MUD) identification, to obtain Sustainability (SUS), operationalized as a second-order formative construct according to the Triple Bottom Line (TBL) framework. The SEM was validated using data from 834 responses to a survey applied to professionals in the manufacturing industry, employing the Partial Least Squares approach in WarpPLS v.8 and the Warp3 algorithm to detect nonlinear relationships, where eight of nine hypotheses were supported. Kaizen influences all three OLTs (5S: β = 0.513; GEM: β = 0.431; MUD: β = 0.227) and had the strongest direct effect on SUS (β = 0.540); however, the GEM→SUS relationship was rejected (β = 0.013, p = 0.357) indicating that GEM improves SUS only through the waste identification (indirect effect: β = 0.154). The model explains 73.6% of the variance in SUS. Beyond validating the hierarchical logic of the Toyota Production System (TPS), this study contributes a formative second-order conceptualization of TBL sustainability as a methodological advance. Two practical implications emerge from this study: building Kaizen as an organizational culture before deploying specific tools and redesigning Gemba Walks as structured dialogues rather than observation exercises.