Vom Labor ins Feld

The mainstream of psychotherapy evaluation had moved away from naturalistic studies like catamnestic ones because their internal validity had to be questioned. The kind of studies which predominated after that have also been criticised in the last few years due to their lack of external and ecological validity. The new approach nowadays is to use controlled field studies which manage to combine the advantages of both previously mentioned evaluation methods. The possibilities with regard to contents and methodological requirements of such studies are described. However, this approach is only possible if it is firmly supported by psychotherapists in the field.