Abstract

A comparison of observational studies and randomized, controlled trials

A comparison of observational studies and randomized, controlled trials. Benson K, Hartz AJ.∗ N Engl J Med 2000;342:1878–1886

It has been claimed that observational studies find stronger treatment effects than randomized, controlled trials. The authors challenged this concept by comparing the results of observational studies with those of randomized, controlled trials. They searched the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition. They then searched the Medline and Cochrane