Despite the increasing recognition for the scientific and societal potential of interdisciplinary research, selection committees struggle with the evaluation of interdisciplinary proposals. Interdisciplinary proposals include a wider range of theories and methods, involve a more diverse team, pose a higher level of uncertainty, and their evaluation requires expertise from multiple disciplines. In this study, we investigate the possibility to support the evaluation of interdisciplinary research proposals with measures of interdisciplinary research quality. Based on the literature, we curated a set of qualitative criteria and bibliometric indicators. Subsequently, we examined their feasibility using interviews with interdisciplinary researchers and a re-assessment session of a grant-allocation procedure. In the re-assessment session members of an original evaluation panel assessed four original research proposals again, but now supported with our measures. This study confirmed the potential of qualitative criteria to assess the interdisciplinarity or research proposals. These indicators helped to make explicit what different people mean with interdisciplinary research, which improved the quality of the discussions and decision-making. The utility of bibliometric indicators turned out to be limited, due to technical limitations and concerns about unintended side effects.