Germany has relied on its well-established tradition of preparing the workforce through the so-called dual system of practical in-firm training (apprenticeships) and theoretical foundations conveyed by vocational schools. Believing in the high quality of academic school programmes that prepare a small elite for university studies, the German public remained convinced until well into the 1990s that there was little need for innovation and improvement in German education. Although there had been earlier signs of concern, this conviction remained unchanged until the publication of the outcomes of the International Association for the Evaluation of Educational Achievement (IEA) Third International Mathematics and Science Study (TIMSS) in 1996. The "TIMSS shock", reinforced by later studies, has resulted in a host of changes in educational policy, perhaps best characterised by the late Hermann Lange as the "turn towards evidence-based educational policy making". Hallmarks of this trend were the decision by all 16 federal states in Germany to participate regularly in international large-scale assessments (ILSAs), including interstate comparisons (taken in 1997); the decision to define standards of educational performance (corresponding to the federally recognised school leaving certificates); the initiation of academic study programmes intended to foster the development of the required advanced technical skills; and the founding and/or expansion of agencies for quality management (including systems of reports on the state of education, both at the federal and the state levels). In this article, the role of ILSAs (including both IEA and others) in these policy changes are described and examined from a critical perspective.