Science is not only created through exchanges of knowledge between academics or experts. This communication describes the networks of experts involved in the fabrication of indicators and benchmarks supporting the Open Method of Coordination. It demonstrates a particular policy of integration between Member States in considering indicators and benchmarks as tools of government. The instrumentation of public action in education is related to the choice and use of tools (technologies, means, devices) to materialize and effectuate the policy agenda of governments and supra-national organizations. Here, the EC has much influence in policy making and States are followers even if they try to defend their national interests. In studying international expertise, we explore the policy borrowing process and the transfer of knowledge between agents and institutions at global level, using Actor-Network-Theory, as developed by Michel Callon and Bruno Latour. For them, instruments of measurement are objects summoned in laboratories and centers of calculation to establish equivalences between different scientific statements and to induce experimentations. These tools stabilize scientific interpretations and transport knowledge across spaces through a process of translation. They are used also to legitimate decisions, to implement contested reforms, to formalize neutral and objective recommendations, etc.