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“Why Should I Care About Systematic Reviews?”

By Joanne Yaffe, Associate Professor, College of Social Work, University of Utah

If you care about public policy or if you care about evidence, you should care about systematic reviews. If you’re an educator, a government official, an economist, a psychologist, a legal analyst, a non-profit manager, or a library and information scientist, you should care about systematic reviews. Why?

Dr. Joanne Yaffe

As a social worker, an educator, and a researcher, my reasons can be best summed up in the ethical code of my profession. The National Association of Social Workers Code of Ethics stipulates that “Social workers should critically examine and keep current with emerging knowledge relevant to social work and fully use evaluation and research evidence in their professional practice.” Many social workers and members of related helping professions believe that systematic reviews represent the best form of evidence for making decisions about practice. So then, what makes these systematic reviews better than any single peer-reviewed journal article?

Let’s start with definition for “systematic review”: Systematic reviews aim to find all (or at least as much as possible) of the research findings related to a well-formulated, practice-relevant question. They employ explicit, replicable methods to locate studies that bear on this question, to critically appraise these studies to evaluate how much we can trust them, and to glean data from only high quality studies. Systematic reviews then go on to synthesize these findings into a form that those who make policy and practice decisions can read.

How is this different from a good old-fashioned literature review? Traditional literature reviews usually examine the results of only a small part of the research evidence, and take the claims of report authors at face value. Because systematic reviews work from an established protocol to find all available evidence, they are less subject to unconscious selection bias, where one tends to find a preponderance of studies that tend to support the researcher’s conclusions. Further, because systematic reviews pre-define the types of studies that will be included in the review and how these studies will be appraised for quality, there is less tendency for reviewers to reject as irrelevant those studies that do not support pre-existing conclusions.

What makes a systematic review better than any single randomized study? Simple: every study has flaws. Systematic reviews combine the results from a number of studies to examine their average effect, rather than to trust the results of any single study. Outliers, that is, studies that produce results very different from other studies, are scrutinized to determine why they are different.

So, why should you care about systematic reviews? Because they enable policy and practice decision-makers to learn from and utilize the best, broadest, most reliable evidence available.

Want to learn more about systematic reviews? Join William Turner of Bristol University, UK, for “Collaborations for Systematic Reviews: You’ll Get Lunch,” Monday, September 20, 2010, 11:30 am – 1:00 pm in room 251 of the Goodwill Humanitarian Building (395 South 1500 East, Salt Lake City).