Something surely must be wrong with epidemiology when the new editors of a leading journal in the field entitle their inaugural offering, “Epidemiology—is it time to call it a day?”1 Observational epidemiology has not had a good press in recent years. Conflicting results from epidemiological studies of the risks of daily life, such as coffee, hair dye, or hormones, are frequently and eagerly reported in the popular press, providing a constant source of anxiety for the public.2 3 In many cases deeply held beliefs, given credibility by numerous observational studies over long periods of time, are challenged only when contradicted by randomised trials. In the most recent example, a Cochrane review of randomised trials shows that antioxidant vitamins do not prevent gastrointestinal cancer and may even increase all cause mortality.4 5

Now Pocock et al describe the quality and the litany of problems of 73 epidemiological studies published in January 2001 in general medical and specialist journals (p 883). …