The Cochrane Database of Systematic Reviews(CDSR) evolved in response to Archie Cochrane's challenge to the medical profession to assemble “a critical summary, adapted periodically, of all . . . relevant randomized controlled trials”.CDSRhas been an electronic publication from its inception and this has meant that Cochrane reviews (i) need not be constrained by lack of space; (ii) can be updated as new information becomes available and when mistakes or other ways of improving them are identified; and (iii) can be cross-linked to other, related sources of relevant information. AlthoughCDSRhas become widely cited, it must continue to evolve in the light of technological and methodological developments, and in response to the needs of people making decisions about health care.

Footnotes IC is indebted to Richard Ashcroft, Angela Coulter, Glyn Elwyn, Paul Glasziou, Jos Kleijnen, Alessandro Liberati, Andy Oxman, Dave Sackett, Trevor Sheldon, Ray Tallis, Hazel Thornton, Jan Vandenbroucke, John Williams, and Kent Woods for helpful comments on an earlier draft of this article. Funding IC receives a part time salary funded by the Medical Research Council and the Department of Health. Competing interests None declared.