Clinical research has led to spectacular developments in health care. It has provided us with knowledge about how to prevent diseases, like heart disease, how to reduce the consequences of disease, such as complications of diabetes, and to alleviate symptoms, such as those of lung disease, and how to rehabilitate people who have suffered a disabling event, such as a stroke. Healthcare systems have the potential to deliver interventions that save lives and improve the quality of life. We know this from well designed research and systematic reviews of that research. Unfortunately, we also know that patients often do not receive effective care when they should, that they sometimes receive care that is not effective or safe, and that not all of the money we spend on health care is well spent. This comes from a different type of research – health services research. In the same way that clinical research is essential for informing how best to care for patients clinically, health services research is essential to inform decisions about how best to organise, finance and govern our healthcare system. This policy brief is a good example of both the potential for health services research to inform healthcare policies and management, and an example of the limitations of health services research to inform decisions.