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The Guide to Community Preventive Services (The Community Guide) Go to site home page About the Task Force


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The Community Guide provides a research agenda for each topic it reviews to point out where more, or better, studies are needed to address questions about effectiveness, applicability and harms. These agendas can help scientists plan and conduct research, as well as secure funding.

Using Insufficient Evidence Findings

Nearly half of current Community Guide systematic reviews result in insufficient evidence findings. This finding does not mean that the intervention does not work; rather it means one of two things:

  • Too few studies of fair to good quality exist to draw conclusions.
  • A sufficient number of studies are found but their results are inconsistent.

If too few studies exist, this may be a reason for conducting additional research. Researchers should consider whether this is simply due to a lack of studies or due to a lack of studies with rigorous methods. If there is a lack of studies with rigorous methods, the evidence gaps section may offer insight into how to design future studies.

If studies exist, but the findings are inconsistent, researchers should consider these questions:

  • Do trends exist in the favorable or unfavorable studies that can be explained by things such as:
    • Sample characteristic (e.g., race, ethnicity, age)?
    • Participation and exposure rates?
    • Historical events (e.g., national crisis or presence of a national media campaign)?
    • Methodological flaws (e.g., a larger number of before-after studies)?
  • Was the intervention applied in a similar enough fashion across all studies to expect consistency?
  • Was the intervention applied correctly in all studies?

Examining the studies included in a review will help researchers consider next steps.

Improving Research Quality

Chapter 12 of the book, The Guide to Community Preventive Services, addresses continuing research needs. It suggests specific ways to improve the quality of intervention research, such as:

  • Setting priorities for topics to review
  • Improving the quality of studies 
  • Identifying theoretical bases via conceptual models
  • Identifying outcome measures

Recently, there have been calls to encourage researchers to consult evidence reviews for information on evidence gaps (and settled research questions) before doing any primary studies.

The Community Guide relies on researchers to conduct studies that can move prevention research forward. It can help you determine which topics need more research and which have been sufficiently studied, so that you can successfully fund your projects and publish findings.

Selected Resources

Agency for Healthcare Research and Quality, External Web Site Icon U.S. Department of Heath and Human Services

The Campbell Collaboration External Web Site Icon

National Institute for Health and Clinical Excellence (NICE) External Web Site Icon

The Cochrane Public Health Group, External Web Site Icon The Cochrane Collaboration