LONDON

THIS month, Johnson & Johnson is facing more than 10,000 lawsuits over an artificial hip that has been recalled because of a 40 percent failure rate within five years. Mistakes happen in medicine, but internal documents showed that executives had known of flaws with the device for some time, but had failed to make them public.

It would be nice to imagine that this kind of behavior is exceptional, but in reality, the entire evidence base for medicine has been undermined by a casual lack of transparency. Sometimes this is through a failure to report concerns raised by doctors and internal analyses, as was the case with Johnson & Johnson. More commonly, it involves the suppression of clinical trial results, especially when they show a drug is no good. These problems would be bad enough on their own, but they are compounded by a generation of “fake fixes” that have delivered false reassurance, and so prevent realistic public discussion.

The best evidence shows that half of all the clinical trials ever conducted and completed on the treatments in use today have never been published in academic journals. Trials with positive or flattering results, unsurprisingly, are about twice as likely to be published — and this is true for both academic research and industry studies.

If I toss a coin, but hide the result every time it comes up tails, it looks as if I always throw heads. You wouldn’t tolerate that if we were choosing who should go first in a game of pocket billiards, but in medicine, it’s accepted as the norm. In the worst case, we can be misled into believing that ineffective treatments are worth using; more commonly we are misled about the relative merits of competing treatments, exposing patients to inferior ones.