This science for policy brief explores the critical role of Interoperability Assessments (IOPA) introduced by the Interoperable Europe Act, which aims to enhance the compatibility and efficiency of cross-border digital public services. By examining the expected benefits, necessary efforts, and potential challenges, this study employs a Wideband Delphi approach to gather expert insights into the intricacies of conducting IOPA. Key findings emphasize the importance of early integration, continuous investment in interoperability capabilities, and the need for cultural and organizational changes to achieve successful implementation. The study also highlights the long-term benefits of investing in interoperability assessments, including smoother implementation processes, higher-quality public services, and significant effort and time savings.