We report on the development of a course for experienced teachers in the Netherlands, intended to enhance their professionalism by engaging them in doing research based on reflection on the aims of their educational efforts. The course was accompanied by design-based research. The research question was whether and how the course stimulated teachers to connect doing research and taking a reflective stance; the results were used to improve the course, thus creating a cyclical design. Although the course was positively evaluated by the participants, reflection on its results made clear to us that our approach in the combination of learning to do research and reflecting on aims is not enough to make teachers into critical research-minded professionals. A more context-aware view of their learning process is necessary: the institution school limits their possibilities. The implication is that both our course and our research effort have to be critically revised. Instead of looking for causal effects, one should be aware of traces of development that may or may not be caused by the intervention.