The quality of decision making in product development (PD) is dependent upon the designer's ability to optimize conflicting needs. However, optimization is unlikely to succeed when based on inaccurate or erroneous information. Given that provision of accurate information frequently lies beyond the designer, decision making is dependent upon effective optimization and a timely flow of accurate information. The present paper explores informal organizational approaches to improving information flow for decision making. It presents an empirical study of relationships in two UK engineering companies and finds significant correlation between the effectiveness of these relationships and the trust, respect, and loyalty that they exhibit during PD. It further identifies the impact of relationship longevity, commonalty in background, and the wider social context of relationships. It concludes by examining the potential extendibility of the findings and the potential for further research to identify interventions that can assist management to enhance the relationships of product developers.