International surveys of literacy have become increasingly important over the last 25 years, organized by a range of agencies including the Organization for Economic Co-operation and Development (OECD), UNESCO and the European Union. National governments commit considerable funding to these surveys and countries then compare themselves against one another other using the results. Curricula, performance indicators and assessments are shaped by these measures. In this process, our views of what counts as literacy, its goals and who literacy learners are, are also formed. Standardised profiles of achievement are highly valued, while at the same time often perceived to be at odds with the everyday literacy practices of both teachers and their students. This chapter describes some of the background to these tests, how they are constructed and the rationales used for them. It argues that a critical engagement with them is essential for anyone currently working in literacy education.