Denmark, Norway, New Zealand, Canada and the US are the OECD countries that spend most on education, measured in relation to GDP. Focusing in particular on upper secondary education, this study paper examines whether the heavy expenditure on education in Denmark is matched by high output from the educational sector, both in terms of a large number of students enrolled in educational programs and a high completion rate. The methodology used compares Denmark with a relevant group of countries and calculates how much cheaper Denmark could teach the same number of students and maintain the same graduation/completion rates as today, if the country could achieve the same level of cost effectiveness as its most efficient counterparts. (Series: The Rockwool Foundation Research Unit - Study Paper - No. 71)