First published in 1991, the ideas embedded in ‘Lay epidemiology and the prevention paradox’ offered a novel and rational explanation for the lay public’s failure to fully engage with the lifestyle messages offered by health educators. During the course of a large ethnographic study in South Wales, Davison and colleagues described the emergence of what they termed the coronary candidate. Candidacy provides a ‘cultural mechanism’ that facilitates the estimation of risk for coronary heart disease. The model has rarely been applied to other major illnesses. This article presents findings from a study that sought to explore the lay epidemiology model, candidacy and cancer. In a series of in-depth individual interviews, members of the lay public discussed their ideas about cancer, and what emerged was an explanatory hierarchy to account for cancer events. Yet the random and unpredictable nature of cancer was emphasised as well as a general reluctance to accept the idea of cancer candidacy.