This paper explores the accountability of two types of multilevel education assessments, the public-law based OECD PISA study and the private-law based assessments carried out by the International Association for the Evaluation of Educational Achievement (IEA). These assessments can be understood as "governance by information", an innovative and powerful type of governance instrument for holding
... [Show full abstract] national policy-makers accountable. Since they constitute an exercise of public power, they need to be accountable in order to be legitimate. An analysis of the accountability mechanisms constraining both types of education assessment on the basis of a model proposed by Grant and Keohane reveals a complex accountability pattern. However, only some of the existing accountability mechanisms are legally institutionalized. Whether this is sufficient, remains an open normative question.