Randomized controlled trials (RCT) are the gold standard in research design for studying causal relationships. In migration studies, they can, for instance, help studying the effects of government and non-government programs on migrant integration. However, RCTs are challenging and cost-intensive to conduct. In this brief, we outline a research design that integrates RCTs into existing panel surveys in order to reduce costs and address certain shortcomings often associated with RCT designs. We introduce the implementation and design of the study and discuss potentials and challenges: How was the RCT integrated into the panel survey? What are the potentials of this research design? What are challenges and pitfalls researchers should be aware of when using this design? To answer these questions, we draw on the study “Mentoring of Refugees” (MORE) as an example, which evaluates a mentoring program between refugees and volunteering locals in Germany, combining the IAB-BAMF-SOEP Survey of Refugees 2017 and 2018 with a randomized controlled trial (RCT).