The health service systems of the Western world are transforming rapidly. These systems are under pressure from an increase of new biomedical possibilities for intervention in the processes of the human body, from the rising expectations of the public, and from demographic developments that are leading to an increase in the number of elderly people in the Western world. Parallel to these changes on the macro level there are major changes on the micro level, that is, there is a search for methods to manage the basic way that the health system functions. In short, the financing, organization and practice of medicine will be changed considerably over the next 5-10 years. In the search for a harmonious development in this field the concept “evidence” must be seen in a broad perspective that encompasses, among other things, the increasing multidisciplinary nature of modern medicine.