TY - JOUR T1 - Measuring overuse: a deceptively complicated endeavour JF - BMJ Quality & Safety JO - BMJ Qual Saf DO - 10.1136/bmjqs-2021-013333 SP - bmjqs-2021-013333 AU - Christine Soong AU - Scott M Wright Y1 - 2021/07/18 UR - http://qualitysafety.bmj.com/content/early/2021/07/18/bmjqs-2021-013333.abstract N2 - Choosing Wisely is a campaign aimed at reducing unnecessary tests, procedures and treatments.1 The goals of the campaign have been to both reduce healthcare expenditures and to prevent harms associated with inappropriate care—such as adverse effects of medications or radiation exposure from unwarranted imaging. The premise is clear and rather simple—do not order something the patient does not need. Yet, when applying a rigorous scientific improvement lens to reducing overuse, measurement nuances make evaluating this phenomenon anything but simple. Appropriateness is specific to clinical scenarios rather than being a representative property intrinsically coupled with individual tests or procedures. Assigning a label of ‘unnecessary’ to a test requires defining the target denominator, which can include a defined patient population, indication and/or test (ie, it is unnecessary to perform imaging for patients with low-back pain without risk factors). When quantifying appropriate use of a test or procedure, differences in the characterisation of the denominator will naturally affect the findings; this makes comparisons challenging when there is a lack of standardisation across measurement methodologies.In this issue of BMJ Quality & Safety, Müskens and colleagues present a systematic review of studies published up to February 2020 reporting the prevalence of low-value diagnostic testing.2 Studies were conducted in both ambulatory care and hospital settings; the findings yield prevalence estimates for the overuse of tests according to relevant guidelines such as Choosing Wisely, ‘Do not do recommendations’, the English National Institute for Health and Care Excellence and those from professional societies. As part of their analysis, Müskens and colleagues classify studies based on the category used for the denominator (referred to as ‘lenses’). Two categories or lenses are identified: (1) the service-centric lens that calculates the proportion of test indications defined as low value and (2) the patient-centric lens that determines the … ER -