This article is a reminder that [[Medicine is complex and messy. It cannot be oversimplified into numbers]]. The McNamara fallacy in medicine is characterised by the following features: (i) the delusion that all of this complexity can yield itself to numerical analysis and control; (ii) over- reliance on crude metrics, such as hospital mortality rates; (iii) the setting of arbitrary targets, many or most of which do not improve patient care, and some of which cause harm; (iv) the pressure of audit and quality assurance programmes on doctors to carry out treatments which are not in the patient’s best interest; (v) the neglect of unquantifiable attributes, such as communication, competence, continuity and compassion. [[O-Mahony-2018-Journal_of_the_Royal_College_of_Physicians_of_Edinburgh.pdf]]