Research Infrastructures as Bottleneck Resources: A Pathway-Based Evaluation of Support in Challenge-Driven Access

This paper evaluates the first three years of a Horizon Europe project providing transnational access to research infrastructures (RIs) for Circular Economy (CE)-related research. Conceptually, the study frames RIs as enabling bottleneck resources whose limited accessibility, technical complexity, and organizational requirements can constrain challenge-driven research and innovation processes. Building on an impact pathway perspective, the paper analyzes how academic users progress from initial contact and proposal preparation to experimental implementation and early research outputs, with particular attention to the role of support mechanisms along this pathway. The study adopts a multi-method formative evaluation approach focusing on process dynamics and intermediate effects during the first three years of project implementation. Quantitative and qualitative evidence from multiple complementary sources is combined to capture both structural patterns of access and mechanisms shaping user experiences and progression. The findings show that dedicated support structures play a central role in lowering access barriers and facilitating progression along the access pathway, particularly for less experienced applicants. Based on the evidence, the paper argues for the concept of centralized support hubs as an important governance and coordination mechanism for challenge-driven RI access. While support mechanisms were consistently evaluated positively, the analysis also indicates that academic transnational access primarily supports activities at medium technology readiness levels (TRLs). For challenge-driven fields such as CE, this suggests that, although dedicated support hubs can effectively mitigate infrastructure-related bottlenecks, additional and differently structured support mechanisms are needed to overcome downstream innovation bottlenecks between research, implementation, and broader socio-technical transition processes.