This chapter examines how ‘useful’ knowledge is generated within the policy domain of migrant integration, shaped by research–policy collaborations mediated by European Union institutions. The chapter asks: What kind of structures are set in place to support migrant integration governance with ‘evidence’, what counts as ‘evidence’, whose expertise is sought out, and what are the implications for wider debates on mobility and diversity? The chapter first maps and classifies the key channels for research–policy collaboration at inter- and supranational (EU) levels, where researchers, policymakers, and practitioners interact to produce, exchange, and disseminate various forms of knowledge on migrants and their integration. Next, it explores the nature of said knowledge, analyzing the various data, statistics, and indicators that are the result of research–policy collaboration. The chapter shows how the EU’s ecosystem of producing evidence for policy not only makes social scientific research indispensable to migrant integration governance, but also constructs ‘integration’ as simultaneosly a measurable, manageable social issue and a collective European problem. Possible implications of this ‘policy-relevant’ knowledge production and its effects on the governance of migranticized and racialized populations are discussed.