Lean Management Model for Sustainable Project Delivery in Egypt: Implications for Off-Site Construction Adoption

Off-site construction depends on reliable planning, coordinated information flow, process stability, workforce capability, and digital integration. These requirements closely align with the organisational conditions needed for successful lean implementation. This paper develops and validates a lean management model for Egypt's construction industry with a specific focus on the critical success factors (CSFs) and their enabling conditions. Building on the research theoretical model, five exogenous constructs - top management support, employee training and engagement, process standardisation, collaboration and communication, and technology and innovation - were operationalised through fifteen enablers and tested using responses from 120 construction professionals. Partial least squares structural equation modelling (PLS-SEM) was employed to examine measurement reliability, convergent validity, and the structural effects of each CSF on lean management outcomes. The results confirm that all five paths are positive and statistically significant. Top management support is the strongest predictor of lean outcomes (β = 0.5235), followed by technology and innovation (β = 0.4591), employee training and engagement (β = 0.3167), collaboration and communication (β = 0.2644), and process standardisation (β = 0.2630). The model explains 76.5% of the variance in lean management outcomes. The paper contributes an empirically grounded framework that translates the original model into an implementation logic suitable for Egyptian construction firms seeking to improve productivity, coordination, and value delivery. The model is rooted in the broader problem of limited awareness, fragmented delivery practices, weak training, and inconsistent leadership commitment in Egypt, which together prevent lean tools from being institutionalised at the firm level. By translating these contextual challenges into CSFs and enablers, the study moves from general advocacy of lean to a measurable implementation architecture.