This paper was prepared as part of the INCLUD-ED Project, an Integrated Project of the 6th Framework Programme of the European Commission. Integrated Projects bring together the critical mass of activities and resources needed to achieve ambitious clearly defined scientific objectives and are expected to have a structuring effect on the fabric of European research. INCLUD-ED was the only project focused on compulsory education which was selected in the last Calls for Proposals of the 6th Framework Programme.