Impact of Supplier Diversity on Procurement Performance in Manufacturing Firms: An Empirical Study

Thesis Abstract

This study investigates how supplier diversity influences procurement performance within manufacturing firms, addressing the persistent mismatch between supplier base heterogeneity and measurable procurement outcomes such as cost efficiency, quality, and resilience to supply chain disruption. The problem stems from limited empirical evidence linking diversity in supplier portfolios to tangible procurement metrics, particularly in mid- to large-scale manufacturing contexts that operate within volatile global markets. The aim is to quantify the relationship between supplier diversity and procurement performance, and to identify moderating and mediating factors that explain this link. Specific objectives are (1) to assess the extent of supplier diversity across manufacturing firms with respect to demographic, geographical, and capability-based dimensions; (2) to examine the impact of supplier diversity on procurement cost, lead time, quality defect rates, and supply chain resilience; (3) to evaluate the mediating role of supplier relationship management practices and procurement flexibility; (4) to explore moderating effects of firm size, industry segment, and sourcing strategy on the diversity-performance linkage; and (5) to develop actionable recommendations for enhancing procurement performance through strategic supplier diversification. Methodologically, the study adopts an explanatory, cross-sectional, mixed-methods design anchored in the Resource-Based View and Transaction Cost Economics theories to interpret how supplier diversity translates into competitive advantages and cost efficiencies. The population comprises 420 manufacturing firms in the automotive, electronics, and consumer goods sub-sectors within a large metropolitan region. A stratified random sample of 180 firms will be selected, with procurement managers and category buyers as the primary respondents for the quantitative component (n ? 180). Complementary qualitative insights will be drawn from 30 in-depth interviews with senior procurement executives to capture contextual nuances and mechanisms. Data collection will employ a structured questionnaire validated through content validity and a pilot test (Cronbach’s alpha target ? 0.80 for all scales), and semi-structured interview guides to elicit perceptions of diversity practices and performance outcomes. Procurement performance indicators will include total cost of ownership, procurement cost savings, supplier delivery reliability, first-pass quality yield, and incident-related disruption frequency over the preceding 24 months. Supplier diversity will be measured along multiple dimensions supplier demographic diversity (ownership gender/ethnicity), geographic dispersion, supplier size diversity, and capability diversity (ESG credentials, innovation capacity). Additional data on control variables such as internal process maturity, supply chain risk exposure, and technology adoption will be collected. Quantitative analysis will proceed with descriptive statistics to profile the sample, followed by confirmatory factor analysis to validate latent constructs. Hypotheses will be tested using multiple regression analyses and structural equation modeling (SEM) to evaluate direct and indirect effects, including mediation by supplier relationship management and procurement agility, and moderation by firm size and sourcing strategy. Robustness checks will include hierarchical linear modeling to account for nested data (plants within firms) and propensity score matching to mitigate selection bias. The qualitative data will be analyzed using thematic analysis, with codes derived both inductively and deductively from the theoretical framework, and then integrated with quantitative findings in a mixed-methods synthesis. Key expected findings include a positive association between supplier diversity and procurement performance, mediated by stronger supplier relationship management practices and enhanced procurement flexibility. The strength of the diversity-performance link is anticipated to vary by firm size and sourcing strategy, with larger firms and diversified sourcing approaches showing more pronounced gains due to better risk pooling and access to a broader knowledge base. The study also expects that geographic and capability diversity independently contribute to performance improvements through supply resilience and innovation capacity, while demographic diversity yields more nuanced gains in reputational and ESG-related procurement outcomes. This research contributes to knowledge by providing robust empirical evidence on how diverse supplier ecosystems influence procurement outcomes in manufacturing contexts, refining the theoretical understanding of diversity as a resource rather than a mere compliance objective, and offering a validated measurement framework for supplier diversity and performance. Practically, the study informs procurement strategy by outlining when and how to diversify suppliers, recommended balance between cost and resilience, and how to structure supplier relationship management to maximize the benefits of diversity. The main conclusion is that strategic supplier diversity, when embedded in proactive relationship management and agile procurement processes, enhances procurement performance, particularly in volatile environments. Recommendations include implementing diversity dashboards, establishing tiered supplier development programs, and aligning diversity objectives with overall supply chain risk management and innovation strategies. Further research could explore longitudinal effects of diversity interventions and sector-specific dynamics across emerging markets.