Issues with the conceptualization, implementation and interpretation of the OECD Programme for International Student Assessment (PISA) are examined. The values that underpin the project are discussed. What PISA is intended to measure (preparation for life, key competencies, real-life challenges, curriculum independence) is contrasted with what it probably measures. Issues are identified relating to cultural fairness (quality and equivalence of translations, anglophone origins, response styles, importance accorded to the test) and the representativeness of participating populations (samples, response rates, adjustment for nonresponse).