Just-In-Time Inventory Management and Organizational Performance in the Manufacturing Sector in Rivers State, Nigeria

Just-in-time (JIT) inventory management has been theoretically proposed as a lean operational strategy capable of enhancing cost efficiency, product quality, and operational flexibility within manufacturing environments. Yet empirical evidence of its impact within the Rivers State manufacturing context characterized by supply chain fragility, infrastructure deficits, and a competitive industrial landscape remains limited. This study investigates the impact of the JIT inventory management approach on cost efficiency, product quality, and operational flexibility among manufacturing firms in Rivers State, Nigeria. Grounded in the Lean Production Theory and the Resource-Based View (RBV), a descriptive survey research design was adopted. Primary data were obtained from 243 respondents comprising production managers, supply chain coordinators, inventory officers, and plant supervisors drawn from 35 purposively selected manufacturing firms across Rivers State. The study yielded 219 valid responses (response rate = 90.1%). Validated instruments achieved strong psychometric properties (Cronbach's α = 0.87 0.90; Content Validity Index = 0.92). Data were analyzed using IBM SPSS Version 27 through descriptive statistics, Pearson correlation, and simple linear regression. Results show that JIT adoption significantly predicts cost efficiency (β = 0.641, R² = 0.411, F(1,217) = 150.24, p < .001), product quality improvement (β = 0.627, R² = 0.393, F(1,217) = 140.56, p < .001), and operational flexibility (β = 0.618, R² = 0.382, F(1,217) = 133.74, p < .001). All three null hypotheses were rejected. The study recommends that manufacturing firms in Rivers State develop structured JIT implementation roadmaps integrated with supplier development programmes, that regulatory bodies issue an industry-level JIT adoption framework for the Nigerian manufacturing sector, and that future research investigate the moderating role of supply chain resilience in the JIT-performance relationship within the Nigerian context.