Editor—A paradox with early detection is that its popularity bears little relation to the magnitude of its benefits and harms. Sarah Stewart-Brown and Andrew Farmer's editorial about screening could therefore be dismissed by some people as public health negativism.1 There is sparse evidence that subjects suffer psychological morbidity, so why worry?

Consider what happens when we screen 250 000 women for cervical cancer. The aim is to help a subset of the 40 or so women who would die annually of cervical cancer among this …