In their reflective article the authors discuss three central issues in the debate on teacher research. First, they argue for a limited and specific use of the term "research" or "study" to avoid the risk of trivialization, erosion or reduction of the term to reflection or problem solving activities. According to the authors the term 'research' in teacher research should be reserved for forms of systematic and intentional behavior to collect and analyze data on specific practices that results in a better understanding of these practices and, in the writing up of the research, imparts meaning beyond the local context. Criticizing the hegemony of effectiveness studies (what works?) in the educational research agenda, they secondly discuss a broader interpretation of research in terms of understanding and insight, genuine interest and curiosity as legitimate elements in an educational research. Finally, they argue for a sustained collaboration between teachers and trained researchers as the best guarantee for relevant and valuable teacher research. Complementary competence and professional learning communities should be the regulative ideas in establishing this collaboration and putting it into practice.