The 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.

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.  The 'Evidence Pyramid' depicts the levels of evidence provided by different types of studies and information in clinical medicine. 

The evidence pyramid shows five levels of evidence and the relative abundance of each one.  The lowest level of evidence pictured with the highest number of studies is case series and case reports.  Second to the bottom is case-control studies.  In the middle is cohort studies.  Second to top is randomized controlled trials.  At the top, and illustrating the smallest relative number of studies, is systematic reviews.


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.  It may involve a meta-analysis. 

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

The Cochrane Collaboration is an organization that performs systematic reviews for clinical medicine interventions and provides guidance for methodology.