achievement of students in other countries? Do some countries stand as existence proofs for the possibility of higher levels of achievement? Another piece of this argument concerns hypothesis generation: By studying education in other countries, alternative approaches to teaching and learning may be discovered. When alternative practices occur in unusually high-achieving countries, they may suggest hypotheses for how education in low-achieving countries might be improved. Of course, countries differ in so many ways that one cannot simply interpret associations between alternative practices and high student achievement as matters of cause and effect. Furthermore, because cultures differ across countries, sometimes quite sharply, it may be that practices in one country cannot be replicated in another. Still, hypotheses about potentially more effective educational practices have been generated by international studies of student achievement, and they can be tested for their feasibility and effects. For example, an analysis of TIMSS (Schmidt, McKnight, & Raizen, 1996) concluded that U.S. mathematics and science education, in comparison with that of higher achieving countries, is characterized by a “splintered vision” and that the United States must strive to create a curriculum with greater focus and less redundancy across grades. Standards-based reform could be seen as testing that hypothesis.

Another reason why international comparative studies of student achievement are useful is that, at least in the United States, policy makers often view them as more authoritative than within-country research. For example, the highly visible and influential report A Nation at Risk (National Commission on Excellence in Education, 1983) used international surveys of student achievement results to argue, “The educational foundations of our society are presently being eroded by a rising tide of mediocrity that threatens our very future as a nation and a people” (p. 5). Unquestionably, the inflammatory language of the report had a great deal to do with its influence. Still, it was largely the international comparative data on student achievement, showing the United States as ranking low among other countries, upon which the report built its case. There was plenty of within-country data on which the report might have built its case, including the declines in National Assessment of Educational Progress (NAEP) and Scholastic Aptitude Test (SAT) scores during the 1970s.

There is at least one more purpose that international comparative studies of student achievement can serve—contributing to the advance of methodology. As is clearly documented in this volume, international comparative studies are complicated and difficult to do well. Over the past 40 years, many methodological advances have been made in the context of this international comparative work, and these advances have strengthened the quality of education research within the United States. The de-