Martijn is trained as social scientist and worked for several years as Junior Researcher for the Cultural Geography Group at Wageningen University. He obtained his PhD degree at Erasmus School of Health Policy & Management (Erasmus University Rotterdam), critically examining how policy experimentation contributes to the overcoming of tensions amongst actors involved in Dutch healthcare governance. He continues to work at Erasmus School of Health Policy & Management as Assistant Professor. Martijn has strong interests in social theory and different conceptions of healthcare, politics and practice. He draws on current advances in the literature(s) on Professionalism and Science and Technology Studies – as well as Public Administration and Political Theory – to explore the diverse and intricate connections between professionalization, rationalization, and politization. Whilst doing so, he particularly focusses on professional groups that work on the (re)organization and (re)valuation of their work within the layered institutional context of the Dutch healthcare system. He typically uses qualitative research methods (e.g. ethnographies and historical case studies) to study these professional groups in formation. Currently, Martijn is studying the (re)professionalization of Dutch nursing work. In the Netherlands, hospital boards, nursing associations, educators and policymakers are trying to differentiate between different kinds nurses and the work they do. Nurse differentiation promises to strengthen the position of nurses in healthcare organizations and to contribute to higher quality, responsive and affordable healthcare. It however also involves rethinking what nurses are, what nurses (can) do and how their work should be measured, valued, and regulated. Martijn aims to foreground the emotional, relational, and political dimensions of this professionalization project. Other research projects are the role of evidence-based decision-making in layered healthcare systems, the role of banks and health insurers in Dutch healthcare governance and a reflexive exploration of the epistemological politics in action-based research.