Résumé : This article examines the various roles that indicators, as boundary objects, can play as a science-based evidence for policy processes. It presents two case studies from the EU-funded POINT project that analyzed the use and infl uence of two highly different types of indicators: composite indicators of sustainable development at the EU level and energy indicators in the UK. In both cases indicators failed as direct input to policy making, yet they generated various types of conceptual and political use and infl uence. The composite sustainable development indicators served as "framework indicators", helping to advocate a specifi c vision of sustainable development, whereas the energy indicators produced various types of indirect infl uence, including through the process of indicator elaboration. Our case studies demonstrate the relatively limited importance of the characteristics and quality of indicators in determining the role of indicators, as compared with the crucial importance of "user factors" (characteristics of policy actors) and "policy factors" (policy context).