The OECD Programme for International Student Assessment (PISA) is probably the most prominent signpost for the internationalization of educational policy. The PISA reports on the performance of secondary school students have become an important factor for educational policy-making in the developed world. In some states PISA has spurred more educational reforms than anything before it during the last decades. What is more, PISA succeeded in shifting approach and focus in a most sensitive area of domestic policy touching on social justice and the self-understanding of the citizenry: Because of PISA, policy-making in the field of school education changed from normative, input-oriented reasoning to comparative, empirical, output-oriented analysis. The international plane succeeded in establishing itself as indispensable in a field thus far essentially conceived as domestic. PISA owes its impact on educational policy to a mode of governance which we call "governance by information". It describes mechanisms which impact on a given policy field by shaping the cognitive framework of policy-making through the collection, processing and dissemination of information. International and supranational institutions more and more often take recourse to governance by information. This article explores the repercussions of governance by information for international law in an approach that stresses the publicness of public international law and the role of international institutional law in legally framing global governance. Thus far, these questions have been hardly explored, in spite of the enormous impact of PISA on national policy. We hypothesize that this is because the knowledge and experience of international lawyers relate mostly to international treaties and other binding legal instruments. Governance by information, by contrast, determines society indirectly through instruments which establish or contribute to the cognitive setting within which policy-makers operate. But since no legal obligations are imposed upon states or individuals, it escapes the established perspective of international lawyers, just as many other instruments, actors and processes of global governance do. In the article, we first provide an overview of PISA and its legal framework (II). Thereafter, we explain why PISA should be considered an exercise of public authority and why it therefore needs a solid public law framework. This part develops a concept of international public authority that focuses on the social relevance of official acts and their impact on individual freedom (III). Third, we explore on a theoretical level how a legal framework could be established for new forms of public authority. In the tradition of German and Italian public law scholarship we suggest the doctrinal construction of "standard instruments" (Handlungsformen). This doctrinal construction does not rest on the belief that legal concepts automatically evoke legitimacy. Rather, it stresses the communicative function of legal doctrine, which provides a stable basis for the exercise of authority while at the same time serving as a forum for contestation (IV). In the following part, we construct and propose a standard instrument called "National Policy Assessment" (Politikbewertung) which is designed to grasp the thrust of PISA and similar policies in a legally significant manner (V). Subsequently, the legal regime of National Policy Assessment is developed by identifying basic legal elements within the legal framework of PISA which we deem instrumental for the legitimacy and effective functioning of this standard instrument. Those elements relate to the mandate on which National Policy Assessment needs to be based, the respect for scientific standards and the representativeness of expertise, access to the assessment data, and national ownership of the assessment results. After a critical appraisal of these elements, we consider the repercussions of the legal regime of National Policy Assessment thus established for other international institutions venturing in the area of education. The example of PISA demonstrates that governance by information is based on a quite elaborate legal framework. Standard instruments are a useful doctrinal category for abstracting basic legal elements and principles from this legal framework, which adds to the legitimacy and effectiveness of the authority thus exercised. This abstraction also enables criticism from various theoretical vantage points. Moreover, the establishment of standard instruments gives policy-makers in international institutions a resource for transposing this type of governance to other issue areas. Once such a legal regime is sufficiently complex to ensure legitimacy and efficiency, it might be applied to other areas. In this respect, doctrinal conceptualization has a rationalizing and clarifying effect. Lastly, we see National Policy Assessment as a valuable tool for holding national governments accountable for their performance. As performance has an impact on the legitimacy of public authority, it would be worthwhile to consider to what extent national governments might be obliged de lege ferenda to expose themselves to such accountability mechanisms. As states are less and less able to meet the needs of a globalized world, and as their citizens and economies must compete on worldwide markets, the legitimacy of the state-based structure of the international legal order might fade if states do not continue to perform on a high level
