The Cochrane Collaboration is a group of over 27,000 volunteers in more than 90 countries who review the effects of health care interventions tested in biomedical randomized controlled trials. A few more recent reviews have also studied the results of non-randomized, observational studies . The results of these systematic reviews are published as "Cochrane Reviews" in the Cochrane Library.

The logo of Cochrane Collaboration illustrates a systematic review of data from seven randomized controlled trials ( RCTs), comparing one health care treatment with a placebo in a forest plot. The diagram shows the results of a systematic review on inexpensive course of corticosteroid given to women about to give birth too early ??? the evidence on effectiveness that would have been revealed had the available RCTs been reviewed systematically a decade later. This treatment reduces the odds of the babies of such women dying from the complications of immaturity by 30???50%. Because no systematic review of these trials had been published until 1989, most obstetricians had not realised that the treatment was so effective and therefore many premature babies have probably suffered or died unnecessarily.

The Cochrane Collaboration was founded in 1993 under the leadership of Iain Chalmers. It was developed in response to Archie Cochrane's call for up-to-date, systematic reviews of all relevant randomized controlled trials of health care.

Cochrane's suggestion that the methods used to prepare and maintain reviews of controlled trials in pregnancy and childbirth should be applied more widely was taken up by the Research and Development Programme, initiated to support the United Kingdom's National Health Service. Funds were provided to establish a ' Cochrane Centre', to collaborate with others, in the UK and elsewhere, to facilitate systematic reviews of randomized controlled trials across all areas of health care.

The goal of the collaboration is to help people make well informed decisions about health care by preparing, maintaining and ensuring the accessibility of systematic reviews of the effects of health care interventions.

The principles of the Cochrane Collaboration are:

• collaboration

• building on the enthusiasm of individuals

• avoiding duplication

• minimizing bias

• keeping up to date

• striving for relevance

• promoting access

• ensuring quality

• continuity

• enabling wide participation

• Evidence-based medicine

• Cochrane Library

• Systematic review

• The Cochrane Collaboration web site Home.

• Most popular 50 Cochrane reviews