Education as a road to growth has been on the political agenda in recent years and promoted not least by the institutions of higher education. At the same time the universities have been squeezed for resources for a long period and the average class size has increased as a result. However, the production technology for higher education is not well known and this study highlights the relation between class size and student achievement using a large dataset of 80.000 gradings from the Aarhus School of Business. The estimations show a large negative effect of larger classes on the grade level of students. The type of exam also has a large and significant effect on student achievements and oral exam, take-home exam and group exam reward the student with a significantly higher grade compared with an on-site written exam