What Is a Systematic Review?
A systematic review is a methodical and comprehensive literature review focused on a particular research question.
Its aim is to identify and synthesize all of the scholarly research on a particular topic in an unbiased, reproducible way to provide evidence for practice and policy-making. It may involve a meta-analysis.
Systematic reviews are considered the pinnacle of research evidence in terms of types of studies (see the Evidence Pyramid).
For example, the Cochrane Collaboration is an organization that performs systematic reviews for clinical medicine interventions and provides guidance for methodology.
Challenges of Evaluating Evidence-Based Interventions
While there are well-established methods for finding and evaluating evidence in clinical settings, finding and assessing evidence for population- and community-based public health interventions presents unique challenges. For example, the literature in this area can be broadly multi-disciplinary, making it important to draw from numerous resources.
Much of the literature may be found outside of published, peer-reviewed journals, on organizational or government websites. Additionally, reporting standards for interventions vary widely, resulting in additional challenges for evaluating whether or not an implementation method will be effective in your setting of interest.
Here are some key articles discussing the challenges and providing guidance for evaluating evidence for public health interventions:
- Criteria for Evaluating Evidence on Public Health InterventionsRychetnik, L., Frommer, M., Hawe, P., & Shiell, A. (2002). Criteria for evaluating evidence on public health interventions. Journal of epidemiology and community health, 56(2), 119–127. https://doi.org/10.1136/jech.56.2.119
- Evaluating the Relevance, Generalization, and Applicability of Research: Issues in External Validation and Translation MethodologyGreen, L. W., & Glasgow, R. E. (2006). Evaluating the relevance, generalization, and applicability of research: Issues in external validation and translation methodology. Evaluation & the Health Professions, 29(1), 126–153. https://doi.org/10.1177/0163278705284445
- From Knowing to Doing A Framework for Understanding the Evidence-into-Practice AgendaNutley, S., Walter, I., & Davies, H. T. O. (2003). From knowing to doing: A framework for understanding the evidence-into-practice agenda. Evaluation, 9(2), 125–148. https://doi.org/10.1177/1356389003009002002
- Reporting of Context and Implementation in Studies of Global Health Interventions: A Pilot StudyLuoto, J., Shekelle, P. G., Maglione, M. A., Johnsen, B., & Perry, T. (2014). Reporting of context and implementation in studies of global health interventions: A pilot study. Implementation Science, 9(1), 57. https://doi.org/10.1186/1748-5908-9-57
- Women’s Groups to Improve Maternal and Child Health Outcomes: Different Evidence Paradigms Toward Impact at ScaleWomen’s groups to improve maternal and child health outcomes: Different evidence paradigms toward impact at scale. (2015). Global Health: Science and Practice, 3(3), 323–326. https://doi.org/10.9745/GHSP-D-15-00251
Evidence Pyramid: Assessing the Quality of Evidence
Not all scientific studies are created equal! Study design significantly impacts the strength and quality of evidence that a study offers.
This Evidence Pyramid depicts the levels of evidence provided by different types of studies and information in clinical medicine. The first level (and lowest) is editorial and expert opinion. The second level is case series and case reports. The third level is case-control studies. The fourth level is cohort studies. The fifth level is randomized controlled trials. The sixth and highest level is systematic reviews.
