Bridging boundaries: Antecedents and consequences of external relationship quality in project portfolios

Organizations actively involve external partners in their project activities to access valuable knowledge, expand their resource pools, and enhance the quality of project outcomes. Research shows that participating in interorganizational collaboration is crucial to fostering the organization’s competitive edge. While previous studies have assessed the importance of external collaborations on the project level, research on the role of external partners on the project portfolio level is scarce. Applying a relational view, we studied 116 project portfolios from medium to large-sized organizations across different industries and assessed antecedents and consequences of external relationship quality at the project portfolio level. Our findings indicate that maintaining high-quality relationships with external project partners across the portfolio is positively associated with overall portfolio success and, eventually, business success. Results further indicate that cultural support and structural formalization are critical portfolio-level antecedents to external relationship quality. When testing for the interaction of the cultural and structural antecedents, we find that culture and structure act as substitutes; a highly supportive culture can balance out low formalization and vice versa. By shedding light on the antecedents and consequences of external relationship quality in project portfolios, our research adds to the understanding of project portfolio management in its context. It gives practitioners new insights into mechanisms that need to be considered when opening project portfolios to external partners. • High-quality external relationships relate positively to portfolio and business success • Cultural support fosters high-quality relationships with external project partners • Structural formalization equally fosters external relationship quality • Culture and structure act as substitutes in shaping external relationship quality