Who needs our data? Lessons from an audience-centred approach in the Geological Service for Europe project

Scientific projects and initiatives are typically designed around scientific excellence and technical capability, treating policy relevance as a secondary consideration rather than a design driver. This places primary emphasis on outputs, assuming that scientific robustness alone is sufficient to ensure their uptake in policy processes. In practice, decision-makers are a diverse set of actors operating under different mandates, timeframes, legal responsibilities, and risk considerations, all of which condition whether and how scientific knowledge can be used to inform their decisions. Drawing on experience from the EU-funded Geological Service for Europe (GSEU) project, we argue that effective geoscience-policy engagement starts with clearly identifying who the outputs are for and how these actors define usable knowledge.GSEU brings together European Geological Survey Organisations to provide harmonised subsurface data, information, tools, and knowledge at continental scale. In doing so, it offers an opportunity to explore the challenges and opportunities of engaging with EU institutions, which constitute the project’s main target audience. We reflect on lessons learned from attempting to align scientific outputs with specific decision contexts, including those related to critical raw materials and CO2 storage.We highlight the importance of early identification of key actors, mapping their needs and expectations, continuous dialogue with stakeholders working at the science-policy interface, and iterative adaptation of scientific outputs to decision-makers’ needs. We also discuss some of the challenges, such as communicating uncertainty and navigating the mismatch between scientific and policy timelines.By arguing for a focus on the “who” before the “what,” we aim to provide transferable insights for geoscientists seeking to engage more effectively in policy design.