This paper analyses the ethics of routine measurement for healthcare improvement. Routine measurement is an increasingly central part of healthcare system design and is taken to be necessary for successful healthcare improvement efforts. It is widely recognised that the effectiveness of routine measurement in bringing about improvement is limited—it often produces only modest effects or fails to generate anticipated improvements at all. We seek to show that these concerns do not exhaust the ethics of routine measurement. Even if routine measurement does lead to healthcare improvements, it has associated ethical costs which are not necessarily justified by its benefits. We argue that the practice of routine measurement changes the function of the healthcare system, resulting in an unintended and ethically significant transformation of the sector. It is difficult to determine whether such changes are justified or offset by the benefits of routine measurement because there may be no shared understanding of what is ‘good’ in healthcare by which to compare the benefits of routine measurement with the goods that are precluded by it. We counsel that the practice of routine measurement should proceed with caution and should be recognised to be an ethically significant choice, rather than an inevitability.