Healthcare decision makers—including clinicians and other healthcare providers—increasingly turn to systematic reviews for reliable, evidence-based comparisons of health interventions. Systematic reviews identify, select, assess, and synthesize the findings of similar but separate studies. They can help clarify what is known and not known about the potential benefits and harms of drugs, devices, and other healthcare services. But the quality of systematic reviews varies; often the scientific rigor of the collected literature is not scrutinized or there are errors in data extraction and meta-analysis.
In the Medicare Improvement for Patients and Providers Act of 2008, Congress directed the IOM to develop standards for conducting systematic reviews. In this report, the IOM recommends standards for systematic reviews of the comparative effectiveness of medical or surgical interventions (see the list of the standards). The standards are meant to assure objective, transparent, and scientifically valid systematic reviews. The evidence base for how best to conduct systematic reviews is limited, and no set of standards is generally accepted or consistently applied. For example, there is little research on how to manage bias for individuals providing input into the systematic review, or on who should screen and select studies for the review. In developing its standards, the IOM relied on the current methodological evidence and guidance from respected organizations that produce systematic reviews. The IOM's standards address the entire systematic review process, from locating, screening, and selecting studies for the review, to synthesizing the findings (including meta-analysis) and assessing the overall quality of the body of evidence, to producing the final review report.