The aim of the article is to describe and discuss how the interview method »DOK« can constitute a foundation for evaluating to what extent clients in a unit for treatment

of substance abuse have their needs met during the treatment period.

The study is based on a case where the data was collected via structured interviews in connection with the beginning and end of treatment. In total 41 clients were interviewed by the DOK interview method.

The case study shows that the data contributes to identifying changes during the treatment period within many different

areas of life. This gives a more comprehensive and balanced picture of the clients’ changes on both an individual and a group

level. The latter gives insight into the treatment delivered, both in life areas where the clients’ needs were met, and in areas where their required support was not received, thus creating a foundation for quality and method development. Evidence-based

practice, and research trying to identify effective treatment methods, requires basic and continual documentation about the clients, and the interventions in the substance abuse care. The study can serve as an example of how structured interviews can constitute a foundation for an evaluation per treatment unit.