Since the late 1990s there has been a fundamental shift in the way schooling and even education as a whole is evaluated. From this new perspective the education system would seem to be interpreted as a sub-system of the economic system and thus subservient to it. Decisions on education matters seem to have become determinant for individual prosperity and decisions on the education system crucial for national welfare. In line with this view, which is rooted in the economics of education and human capital theories of the 1960s, international studies have been designed under the auspices of the OECD in the hope of obtaining more and better data for control purposes. This paper argues that such hope is not justified. Using Germany as an example, the practical consequences of these assumptions, which appear to be arbitrary, if not counter-productive, and the resultant changes in education policy based on the related control data will be described. (Contains 1 table.)