Chapter 30 focuses on issues relating to norm-referenced measures, in particular the use of norms in international assessments. This chapter highlights some of the complex issues involved in norming scores. While the initial sections of the chapter review some general issues of norm construction and use, this is not a chapter on the mechanics of how to produce norms. Rather, it focuses on issues of when and how to use norms, what aggregations of samples to base them on, and how norm-referenced scores should be interpreted. In particular, it considers issues relating to the development and use of international norms. Test norms are often essential for stakeholders to understand the meaning of test scores by providing information about the standing of the test taker relative to other members of the population. Finally, the chapter notes that culturally related variance may reflect either measurement bias or effects of cultural style.