“Upon this gifted age, in its dark hour, Rains from the sky a meteoric shower Of facts.... they lie unquestioned, uncombined. Wisdom enough to leech us of our ill Is daily spun, but there exists no loom To weave it into fabric”. Edna St Vincent Millay. Millay EStV. Collected sonnets. New York: Harper and Row, 1988:140

Archibald Cochrane said “It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials”.¹ It was in answer to this “criticism” that the Cochrane Collaboration was set up.

The modern practice of medicine necessitates that where feasible our practice should be based on the best available information. We can search for this ourselves, but where a rigorously conducted systematic review has been undertaken by a group of people with a specific knowledge and interest in the question you seek to answer, it would seem foolhardy to ignore it or under estimate its significance. This Cochrane Database of systematic reviews is a rapidly expanding collection of regularly updated systematic reviews of research on the effectiveness of health care.

At the time, our work was undertaken there were 52 Collaborative Review groups.

Each group being made up of institutions and individuals who share an interest in generating reliable up to date evidence relevant to the prevention, treatment, and rehabilitation of particular health problems. These groups had produced 1750 articles.

Each of these in turn is a complete review or protocol (that is, review in preparation) of studies that …