Screening, scale and certainty

Abstract

A common concern about screening programmes is that there is much uncertainty about their effects. Using the example of CT-based screening for lung cancer, this paper explores the sources of uncertainty and possible strategies for reducing uncertainty. Specifically, it suggests that there is an epistemologically and ethically significant distinction between “individual-level” and “population-level” uncertainties, such that reducing uncertainty in the interpretation of images may not reduce the uncertainties which are most practically relevant.