This chapter analyses and compares recent changes in school accountability in Norway, Denmark and Sweden, focusing on the role of standardized performance tests as a policy instrument for school improvement and accountability. The links between national testing and translations and enactments are discussed, including re-centralization processes in decentralized school systems under the auspices of a universal welfare state model, and how global policy is translated and adapted in different national contexts. The analysis illustrates the importance of national trajectories and translations of global ideas and argues that the concept of ‘instrument constituencies’ may help in understanding the complexities and transformation of accountability and governance practices.