This thesis investigates how value is co-created and perceived between public clients and consultants during the front-end stages of infrastructure projects, where early decisions critically shape long-term outcomes. Drawing on a qualitative multi-case study of two Dutch infrastructure projects, the research identifies key resources, co-creation processes, and value outcomes generated. In addition, the study also emphasizes the role of human-centric and contextual factors, such as strategic priorities and structured service approaches, in influencing decision-making quality. The study offers practical recommendations which include early market engagement, iterative knowledge development, and co-created reporting frameworks to enhance collaboration and reduce delays. The visual framework developed serves as a reference for project managers to evaluate the effectiveness of co-creation process and improve value delivery in complex infrastructure projects.