• Applied and Professional Ethics
• Clinical Ethics
• Concept of Health
• Epidemiology
• Philosophy of Medicine

Overdiagnosis is a significant problem for healthcare, harming individuals and incurring costs. One potential barrier to addressing overdiagnosis concerns the difficulty of pinning down exactly what we mean by the term. To this end, Carter et al make a welcome contribution to the growing debate.1 In particular, the authors raise important points about the social harms of overdiagnosis and the need for structural interventions; their typology is useful for discussing ethical issues in specific cases of overdiagnosis and may ground legal and institutional actions; and they contribute to investigation of the psychological and sociological processes that lead to overdiagnosis. Our main reservation hinges on their definition of overdiagnosis, which we feel may fail to map current usage.

On their account, overdiagnosis of condition A in a population occurs when that condition is correctly identified and labelled (diagnosed) but the diagnosis and/or intervention is, on balance, more harmful than beneficial. The correctness of the diagnosis relies upon acceptance by a relevant professional community. Overdiagnosis must be defined at a population level, given the difficulties of knowing which specific individuals diagnosed with condition A suffer more harm than benefit.

The authors' definition seeks to explicate key features attributed to overdiagnosis, namely that the diagnosis is correct but that there is no benefit. They start by characterising the “rough meaning-in-use for overdiagnosis [as] ‘a correct diagnosis that does not benefit’” (ref. 1, p. 2). This claim follows numerous quotations from the literature summarising dominant views about the nature of overdiagnosis. These views are remarkably consistent in their central claim, namely that overdiagnosis involves a condition or disease that would: ‘not have harmed’;2 ‘not present symptomatically’;3 ‘never cause symptoms or death’;4 ‘not have been identified clinically’5 and so forth. In turn, many of these views are based upon …