Like politicians, doctors are inclined to believe that doing something (especially when it is them doing it) is better than doing nothing. They mistake benevolent intentions for good results, believing that the first guarantee the second. How can philanthropy go wrong?

Besides, doing something stimulates the economy in a way that doing nothing cannot possibly match. If people did only what was necessary, or what was good for them, or what was right, the whole of our economy would soon collapse.

Be that as it may, and for whatever reason, clinical trials that have positive results are more likely to be published than those with negative results. Thanks to several well-publicized scandals, this publication bias, as it is called, is on the decline. GlaxoSmithKline, one of the largest pharmaceutical companies in the world, has promised that henceforth it will publish the results even of trials that are unfavorable to their products as well as those that are favorable.

A paper by Danish researchers just published in the British Medical Journal assesses the extent to which published reports of trials of screening procedures, such as mammography, colonoscopy, PSA-levels, etc., report their harmful effects and consequences as well as their positive ones.

This is particularly important ethically because screening reverses the usual relationship between patient and health-care system. In screening it is the health-care system that initiates the contact, not the other way round. Screening is offered to healthy people, or at least to those complaining of nothing; moreover, the chances of benefit from screening are often slight and those who do benefit from them do so in a sense at the expense of those who are harmed by them. The moral imperative to know the harms of screening is therefore great.