The improvement of public health relies on effective strategies for disease prevention, but the optimal preventive strategy is often difficult to determine. The population attributable fraction is a tool that allows policy makers to prioritise among different interventions by quantifying the share of disease in the population that is due to one specific risk factor. In this article, we discuss the computation of the population attributable fraction, as well as its advantages, limitations, and challenges for proper interpretation. We further compare the population attributable fraction to the etiologic fraction, which concerns the impact of a risk factor of disease at the individual level. We illustrate the importance of either measure, as well as differences between them, on the basis of scenarios in which community medicine and patient-centred care might not always be in agreement.