Diagnostic assessment in TIMSS-R: Between-countries and within-country comparisons of eighth graders’ mathematics performance

The importance and relevance of mathematics knowledge to every day life in the 21 st century has been widely acknowledged. Moreover, from an economical standpoint it is universally recognized that a country whose students excel in mathematics is more likely to establish its competitive advantage in an increasingly global economy. Education systems in many countries are therefore concerned about heir students ' performance in international tests and are seeking ways to improve their mathematics instruction (Wagemaker, 2002). International studies of mathematics achievement such as the Third International Mathematics and Science Study (TIMSS-R) and its predecessors, FIMS, SIMS, and TIMSS, have reported internationally comparable achievement profiles for over four decades (Wagemaker, 2002). Information regarding the attained curricula from an international perspective provides a "calibrated yardstick " which, if carefully and thoughtfully used, could support a country's education system in its effort to prepare an internationally competitive workforce. Attempts to explain differences in mathematics achievement from an international perspective address the effectiveness of education systems as well as the confounding effects of the cultural contexts in which they operate (Martin, Mullis, Gregory, Hoyle, & Shen, 2000; Ramakrishnan, 2000). Yet, there is a portion of score variance in international tests that cannot be accounted for by cultural effects, school effectiveness, and their interactions. That portion is due, at least partially, to the validity of the international test itselt, that is, to the correspondence b tween the test and the intended curricula in th