This paper aims to contribute to the literature relating to the way in which numerical data in IT systems were and are used to govern the development of primary education as data provide the government with the opportunity to 'see' the system of education in a new way. Economic growth in the Western world after World War II was linked to education. New IT-based forms of technology with numerical data could help planning as there was great confidence in numerical data as objective phenomena. The article shows how the Danish Ministry of Education established a number of IT systems during the 1960s and 1970s. Data within the systems provided the Ministry with an opportunity to 'see' the system of education in a new way and thereby change the system. On a wider scale, this article contributes to the present debate on how numerical data is used to govern citizens.