The Relative Importance of Interfirm Relationships and Knowledge Transfer for New Product Development Success*

The relationship and network literature has primarily focused on particular partner types, for example, buyer–supplier relationships or competitor interaction. This article explores the nature and relative importance of different types of interfirm relationships for new product development (NPD) success. The underlying premise of the study is that not only the type of interfirm relationships but also the combination of relationships are important for NPD performance. The interaction with a specific type of partner is expected to influence innovative performance by means of appropriate knowledge transfer. Varying needs for external knowledge, and thus types of relationships, are observed depending on the particular stages in the NPD process, the character of the knowledge base of the firm, and the industrial conditions. The absorption of external knowledge is discussed using the degree of redundancy in knowledge, which is defined as the degree of overlap in the knowledge base of the sender and the recipient of knowledge. Hence, the degree of redundancy has direct implications for the ease and, hence, use of knowledge shared with an external partner. The article is based on data from the Know for Innovation survey on innovative activities among European firms, which was carried out in 2000 in seven European countries covering five industries. The article explores the extent of use of external relationships in collaborative product development and finds that customers are involved more frequently in joint development efforts. Second, the industry association of the most important relationship is studied, and the results show that firms tend to partner with firms from their own industry. The danger in this approach is that firms from their own industry tend to contribute similar knowledge, which ultimately may endanger the creation of new knowledge and therefore more radical product developments. The analyses combine the finding that relationships with customers are used most frequently at both early and late stages of the product development process, with a second and more contradictory finding that at the same time customer relationships have a negative impact on innovative success. Moreover, the combination of customers, with both universities and competitors, has a significant negative effect on innovative performance. The potential causes of this apparent paradox can be narrowed down to two: (1) the average customer may be unable to articulate needs for advanced technology‐based products; and (2) the average customer may be unable to conceptualize ideas beyond the realm of his or her own experience. Based on this evidence the article cautions product development managers to think explicitly about what certain customers can contribute with and, more importantly, to match this contribution directly with their own sense of what direction product development should go in the future. Finally, the role of complementary as well as supplementary knowledge is investigated for innovative success finding that sharing of supplementary knowledge with external partners in NPD leads to a positive effect on innovative performance. The article is concluded by a discussion of the implication of this finding for building knowledge within the firm and for selecting external partners for NPD.