Lean Management Practices, Waste Reduction, and Operational Performance: An Empirical Study of Nigerian Automotive Assembly Plants

This study empirically investigates the effects of lean management practices on waste reduction and operational performance in Nigerian automotive assembly plants, focusing on facilities in Lagos and Kaduna, representing South West and North West geopolitical zones respectively. Nigeria's nascent automotive assembly industry faces significant productivity competitiveness challenges, and lean management offers a systematic pathway for operational improvement. A quantitative case study and survey combined design was employed with 175 production managers, quality control officers, and process engineers as respondents. Partial least squares SEM was used for hypothesis testing. Lean practice dimensions evaluated include value stream mapping application, standardised work implementation, just-in-time delivery practices, kaizen event frequency, and 5S methodology adherence. Waste reduction was measured across defect, overproduction, inventory, and motion waste categories. Findings indicate that standardised work implementation and just-in-time practices generate the most significant waste reduction outcomes, while kaizen event frequency shows the strongest association with sustained operational performance improvements over time. Value stream mapping adoption was found to be low among Nigerian assemblers, representing an untapped efficiency opportunity. The study contributes empirical evidence on lean management applicability in the Sub-Saharan African manufacturing context. Recommendations include structured lean training programmes, investment in value stream mapping capabilities, and establishment of lean improvement centres. Keywords: lean management, waste reduction, operational performance, automotive industry, Nigeria.