Third-Party Logistics Service Quality and Supply Chain Performance: The Mediating Role of Operational Flexibility in Nigerian Manufacturing

This study empirically tests a mediated model examining the effect of third-party logistics (3PL) service quality on supply chain performance, with operational flexibility proposed as a mediating variable, in Nigerian manufacturing firms. Manufacturing firms that outsource logistics functions to third-party providers increasingly depend on those providers' service quality to sustain supply chain performance. However, the mechanism through which 3PL service quality translates into performance gains remains underexplored in the Nigerian context. Using a quantitative design, structured questionnaires were administered to 190 supply chain and operations managers in 38 manufacturing firms using 3PL services across Lagos, Ogun, Rivers, and Kano States. 3PL service quality is assessed through reliability, responsiveness, flexibility, communication quality, and cost competitiveness. Operational flexibility is measured through production schedule adaptability, volume adjustment speed, and logistics mode switching capability. Supply chain performance is operationalised through order fill rate, inventory turnover, and customer delivery lead time. Structural equation modelling with bootstrapped mediation testing is employed. The study draws on service quality theory, operational flexibility literature, and 3PL performance research. Findings are expected to confirm partial mediation, showing that 3PL service quality improves performance directly and indirectly through enhancing the firm's operational flexibility. The study contributes original mediation evidence to a predominantly direct-effects literature on 3PL and supply chain performance in Africa. Recommendations are addressed to manufacturing procurement directors and 3PL service providers on designing contracts that explicitly incentivise flexibility contributions. Keywords: third-party logistics, service quality, supply chain performance, operational flexibility, Nigerian manufacturing.