Treatment contrast in experimental research within welfare and education

This article discusses methodological problems regarding the use of experimental designs within the fields of welfare and education. Experimental designs have become more common in evaluations within these fields; similarly, there are challenges involved in applying them. The interventions evaluated often involve several actors, include multiple levels of implementation and have multiple and interacting mechanisms. Interventions are also often implemented within complex practice contexts and for heterogeneous target groups. In the context of our experimental research, we especially discuss the challenges of a treatment contrast, that is the difference between activities in experimental and control groups, how to understand and tackle it. The article concludes that there is a need for experimental research within the fields of welfare and education, but that experimental designs require measurable interventions and contexts. Our trust in results from experiments depends on the extent to which the requirements are fulfilled.