We found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleWhen are observational studies as credible as randomised trials?AuthorsVandenbroucke JPPublicationLancet, 2004, Vol 363, Issue 9422, p1728ISSN0140-6736Publication typearticleDOI10.1016/s0140-6736(04)16261-2