Identifying three "modes of policy legitimation" in education, illustrated by shifts in Swedish educational assessment and grading policies over the past decades, the paper demonstrates significant trends with regard to national governments' policymaking and borrowing. We observe a shift away from "collaboracy" -- defined as policy legitimation located in partnerships and networks of stakeholders, researchers and other experts -- towards more use of supranational agencies (called "agency"), such as the Organisation for Economic Co-operation and Development, the European Union and associated networks, as well as the use of individual consultants and private enterprises (called "consultancy") to legitimate policy change. Given their political and high-stakes character for stakeholders, assessment and grading policies are suitable areas for investigating strategies and trends for policy legitimation in education. The European Union-affiliated "Eurydice" network synthesises policy descriptions for the European countries in an online database that is widely used by policymakers. Analysing Eurydice data for assessment and grading policies, the paper discusses functional equivalence of grading policies and validity problems related to the comparison of such policy information. Illuminating the roles of the Swedish Government and a consultant in reviewing and recommending grading policies, the paper discusses new 'fast policy' modes of policy legitimation in which comparative data is used to effectuate assessment reform.