This study contributes to the understanding of New Product Development (NPD) performance by demonstrating how formal interfirm collaborative relationships provide access to important information and how the structure of the formal interfirm network impacts NPD in different ways. The study also develops a dimension of networks, network diversity, and its contribution to NPD performance. In exploring how NPD performance is affected by information available between firms with formal cooperation agreements, it suggests that two aspects of the formal external information network, variety and...