Drivers of innovation in infrastructure development projects: A configurational analysis of boundary spanning roles

•Both contractual and relational arrangements contribute to project innovation.•Varying project conditions require distinct combinations of boundary spanning roles.•The types of boundary spanning roles are internal, external and bridging roles.•In low complexity projects, it is best to adhere to standards of practice.•In high complexity projects, boundary spanning roles are integral to innovation. Innovation can provide new opportunities to improve project efficiency. However, enabling innovation is challenging, especially in public infrastructure development projects. Several impeding factors, such as limited contractual incentives and complexity, are prevalent in contract-based collaborative environments. Literature suggests that boundary spanners play an important role in driving innovation by seizing opportunities. This study aims to identify configurations of boundary spanning roles in typical project situations— varying in contract type and complexity— to facilitate innovation. The empirical data is from 58 projects and analyzed using fuzzy-set Qualitative Comparative Analysis (fsQCA). Results show that depending on the project conditions in terms of contract type and complexity, different combinations of boundary spanning roles can be taken up by project managers or other team members to facilitate innovation. This study highlights that in high-complexity situations, boundary spanning roles play a critical role in maintaining good relationships with collaborators, which is instrumental in developing innovation.