Sense about mammography.

breast cancer, from self examination to mammography, reflects the powerful commonsensical appeal of the notion that early diagnosis confers a better prognosis. But, according to Gøtzsche, ‘it has not been proved that screening saves lives’. It may do, but it is clear that the benefit of mammography is relatively small, certainly much smaller than the public — influenced by a combination of wishful thinking and public health propaganda — believes. If the current controversy leads to a less paternalistic and manipulative presentation of health information then this will have much wider benefits. Broadcaster Michael Blastland has shown how the statistics of breast cancer screening can be presented in such a way as to enable women to make an informed choice about mammography. He follows the approach recommended by Professor Gerd Gigerenzer of the Max Planck Institute, who favours presenting absolute rather than relative risks, ‘natural frequencies instead of conditional probabilities’. In an inspirational summary of his approach, Gigerenzer and colleagues insist that ‘statistical literacy’ is ‘a necessary precondition for an educated citizenship in a technical democracy’. Their conclusion emphasises the wider political and social significance of the accurate presentation of information about health: ‘Understanding risks and asking critical questions can also shape the emotional climate in a society, so that hopes and anxieties are no longer as easily manipulated from outside and citizens can develop a better-informed and more relaxed attitude toward their health.’