Structural linkages among lean construction barriers in Chinese EPC projects: evidence from PLS-SEM and firm-size differences

In Engineering, Procurement, and Construction (EPC) delivery, lean construction (LC) adoption often struggles because phase interdependencies, multi-tier supply chains, and shifting requirements weaken coordination and management focus. This study examines structural links among LC barrier domains in Chinese EPC projects and whether they differ by firm size. A six-domain questionnaire was adapted from prior LC barrier research and guided by the Technology–Organization–Environment framework and Contingency Theory, then refined through expert review and pilot checks. Survey data from 456 Chinese EPC stakeholders were analyzed using partial least squares structural equation modeling (PLS-SEM) to estimate structural paths among barrier dimensions, while multi-group analysis (MGA) tested firm-size differences in these paths. Results show that the institutional environment and supply chain complexity are key external pressures, and strategic leadership links them to internal organizational and technical constraints, with size-contingent effects: institutional pressures are stronger in large firms, while supply chain complexity is stronger in SMEs. The study moves beyond barrier ranking by offering a system-level structural model that clarifies barrier ordering and boundary conditions. Policymakers and clients should strengthen rule consistency and procurement governance, while contractors should tailor actions by firm size, strengthening leadership-led coordination in large firms and supply-chain integration in SMEs.