ABSTRACT
Systematic reviews now form the cornerstone of evidence-based decision making. They have risen in prominence over the past 10 years, largely through efforts such as those of the Cochrane Collaboration and investment in research synthesis and dissemination by the UK Department of Health in establishing the NHS Centre for Reviews and Dissemination. Systemic reviews and meta-analyses, however, are nothing new, and this method of synthesising research evidence has its roots in mental health and social science (Smith & Glass, 1977).
