Introduction

Why do people continue to overestimate the benefits of breast screening and PSA screening for prostate cancer? Where do they get their information? What are health professionals and public health information providers telling them? Why are they making apparently irrational decisions about attending?1 How are their perceptions formed?

We learn from a survey2 of a representative sample of 10 228 people conducted in December 2006 that 92% of women overestimated the cancer mortality reduction from mammography screening by at least one order of magnitude or reported that they did not know, and that 89% of men overestimated the benefits of PSA screening by a similar extent or did not know. They were also asked about the extent to which they consulted different sources of health information: the most frequently mentioned sources were general practitioners and pharmacists. Other studies about physicians' lack of knowledge about the benefits of screening support the assertion that it is health professionals who contribute to people's overestimation of benefit.3

Preventive interventions

Preventive interventions can range from the apparently simple, such as hand washing,4 to comprehensive public health screening programmes, such as the NHS Breast Screening Programme or vaccination programmes for MMR. Each presents its own individual challenges for …