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Systematic Review Methods
The Community Guide conducts systematic reviews of interventions in many topic areas to learn what works to promote public health. The Community Preventive Services Task Force uses the results of these reviews to issue evidence-based recommendations and findings to the public health community.
What is a systematic review?
A systematic review is a review of scientific studies on a specific topic. It uses a formal process to:
- Identify all relevant studies
- Assess their quality
- Summarize the evidence
Why do a systematic review?
Systematic reviews help make sense of large bodies of scientific literature by applying the scientific process to:
- Reduce bias in how conclusions are reached
- Improve the power and precision of results
- Summarize evidence about the effectiveness of particular approaches for addressing a public health problem
- Analyze generalizability of findings
- Identify knowledge gaps and need for additional research
Who develops the Community Guide?
Each review is conducted by specialists in systematic review methods and subject matter experts.
How are reviews done?
Community Guide reviews:
- Use methods that address the specific needs of public health
- Use methods developed internally, approved by the Task Force, and published in peer-reviewed journals
- Apply these methods to a broad range of public health topics
- Inform Task Force recommendations and findings
The Community Guide, with guidance from the Task Force, conducts each review using multiple steps.
What are the steps in The Community Guide review process?
- Form a coordination team to guide the review process
- Develop a conceptual framework, called a "logic model" for the review
- Identify and select interventions that the review will cover
- Define and develop a conceptual approach for evaluating the interventions, called an "analytic framework" [PDF - 267 kB]
- Identify criteria for including and excluding studies
- Use the criteria to search for, retrieve, and screen abstracts
- Review the full text of every study and code the data [PDF - 6.81 MB] from each using The Community Guide abstraction form [PDF - 452.2 kB]
- Assess the quality [PDF - 6.81 MB] of each study
- Summarize all of the evidence found, called the "body of evidence" [PDF - 36 kB]
- Identify issues of applicability and barriers to implementation (when available) for recommended interventions
- Summarize information about other benefits or harms that might result from the interventions
- Identify and summarize evidence gaps
- Develop recommendations and findings
- Conduct an economic evaluation [PDF - 833 kB] of the interventions found to be effective
What do recommendations and findings mean?
Each Task Force finding is:
- Based on the strength of the evidence of effectiveness in changing outcomes
- Found through systematic reviews of published literature
- Conducted by a team of experts on behalf of the Task Force
- Meant to be used along with information about local needs, goals, and constraints
Categories of Task Force Recommendations and Findings
The Task Force uses the terms below to describe its findings.
The systematic review of available studies provides strong or sufficient evidence that the intervention is effective.
The categories of "strong" and "sufficient" evidence reflect the Task Force's degree of confidence that an intervention has beneficial effects. They do not directly relate to the expected magnitude of benefits. The categorization is based on several factors, such as study design, number of studies, and consistency of the effect across studies.
The systematic review of available studies provides strong or sufficient evidence that the intervention is harmful or not effective.
The available studies do not provide sufficient evidence to determine if the intervention is, or is not, effective. This does NOT mean that the intervention does not work. It means that additional research is needed to determine whether or not the intervention is effective.
Task Force findings may include a rationale statement that explains why they made a recommendation or arrived at other conclusions.
How are costs and economic benefits evaluated?
If an intervention is found to be effective, the Community Guide evaluates its economic efficiency. This approach is used because the Task Force makes recommendations based on whether or not an intervention is shown to improve health, regardless of its cost and/or economic benefits.
Briss PA, Zaza S, Pappaioanou M, et al. Developing an evidence-based Guide to Community Preventive Services-methods. [PDF - 205 kB] Am J Prev Med 2000;18(1S):35-43.
Zaza S, Wright-de Aguero L, Briss PA, et al. Data collection instrument and procedure for systematic reviews in the Guide to Community Preventive Services. [PDF - 6.81 MB] Am J Prev Med 2000;18(1S):44-74.
Carande-Kulis VG, Maciosek MV, Briss PA, et al. Methods for systematic reviews of economic evaluations for the Guide to Community Preventive Services. [PDF - 3.74 MB] Am J Prev Med 2000;18(1S):75-91.