Heterogeneous Top Management Teams, Strategic Decision Processes, and Firm Innovation in Nigeria

This dissertation examines how heterogeneity in top management team composition influences strategic decision processes and firm innovation outcomes in Nigerian organizations. Upper echelons theory predicts that TMT diversity shapes organizational strategies, yet the role of Africa-specific diversity dimensions, including ethnic diversity, educational background diversity, and international experience diversity, has not been empirically examined in strategic decision-making research. Upper echelons theory, team cognition research, and behavioral strategy theory provide the framework. The study employs a concurrent mixed methods design. A quantitative survey of TMT members and CEOs from sixty Nigerian firms across South West, South East, and North Central zones measured TMT heterogeneity dimensions, decision process quality, and innovation output indicators. Hierarchical regression and interaction analysis were applied. Qualitative comparative case studies of five firms provided process-level insight. Findings reveal that functional diversity and educational diversity in TMTs have significant positive effects on innovation outcomes mediated through constructive decision conflict and information elaboration process quality. Ethnic diversity demonstrates a complex conditional effect: positive innovation effects emerge only in TMTs with established psychological safety cultures and strong integrating leadership. The study makes original theoretical contributions by extending upper echelons theory to incorporate African ethnic diversity as a theoretically and empirically meaningful TMT heterogeneity dimension. Keywords: top management team, heterogeneity, strategic decisions, firm innovation, Nigeria.