What is and is not covered by basic health insurance? How many departments of emergency care are needed to be able to offer quality care throughout the Netherlands? This dissertation describes research into the way in which decisions about the insurance package and the quality of care in the social health insurance are justified. The researcher carried out several-years-worth of ethnographic participatory observations at the National Health Care Institute, which is responsible for ensuring that high-quality healthcare remains affordable and accessible to all Dutch people. This research shows that policymakers use different forms of knowledge - statistical knowledge, clinical knowledge, patient knowledge while making complex policy decisions, but that not all forms of knowledge are regarded as equally relevant, credible and reliable. This dissertation examines the question to what extent the existing knowledge practices of policy makers are adequate and socially representative. Following the philosopher Stengers, the character of the 'idiot' serves to argue that public learning processes are only possible if individuals, with their confused presence, question existing knowledge practices.