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NS 4600: Explorations in Global and Public Health: Evaluating Evidence in Public Health

A guide to evidence-based research in public health.

The challenges of 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.

Steps for searching the literature for evidence

The next pages of this guide provide resources and approaches to finding evidence for public health interventions. Consider the following step-wise approach to conducting your search or adapt it as you see fit. And keep in mind that this is an iterative process!  For details about each step, see the next tab.

  • Identify existing systematic reviews on topics related to your research question. You may find there are no existing systematic reviews (in that case try broadening your search) or that there was already a systematic review conducted on your research topic.  Use the related reviews you find to shape your own search strategy and methods, and look at the references they found to get a sense of the state of the research.
  • Define your research question.  Use a question framework to structure and define your research question.  This will help you structure and build your search strategy and screening process.
  • Plan your search approach.  Identify  what databases and gray literature sources you will search.  How will you organize the results of your searches?  How will you screen the searches for inclusion in your review?
  • Document your process.  Keep track of the databases you search, when you searched them, the search strategies that you used and how many results were found with your searches.

What is a Systematic Review?

A systematic review is a methodical and comprehensive literature review focused on a particular research question.  It's 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.  

Systematic reviews are considered the pinnacle of research evidence in terms of types of studies.  See the evidence pyramid below.

The Cochrane Collaboration is an organization that performs systematic reviews for clinical medicine interventions and provides guidance for methodology.  See the next page for other sources of systematic reviews, some in areas of public health and social sciences.

Assessing the quality of evidence

Not all scientific studies are created equal!  Study design is one aspect that can impact the strength and quality of evidence that a study holds.  This 'Evidence Pyramid' depicts the levels of evidence provided by different types of studies and information in clinical medicine.