A realist review is a type of evidence review that assesses the specific contexts in which a certain intervention may or may not work. This type of review acknowledges the complexity of the health care system and the lives of the people who interact with it — and the fact that change resulting from the implementation of complex interventions can be based on many different variables with potentially different outcomes in different situations.
While a systematic review attempts to determine whether an intervention is effective or not, a realist review asks why an intervention may or may not be successful, under what circumstances, and for whom.
Realist reviews use theory to explore how contexts such as cultural norms and values, economic conditions, geographic characteristics, or national policy interact with various mechanisms to potentially affect patient outcomes and other health benefits. A realist review can produce important information about the relative effectiveness of components of an intervention and help to determine the necessary components of an intervention if it is offered. This allows practitioners, researchers, and service providers to design and implement interventions that include the most effective components.
Many of the steps involved in undertaking a realist review are the same as with a traditional systematic review, including undertaking a literature review, extracting data, and assessing the quality of the data. The data sources considered in realist reviews may include randomized controlled trials, qualitative studies, observational studies, mixed-methods studies, grey literature, and other forms of real-world evidence. This provides researchers with valuable insights on how an intervention will perform in the real world.
Realist reviews are a relatively new approach to assessing the impact of health technologies and interventions. These reviews must also be conducted by those with an understanding of health systems and a specific expertise in social science theory.
The assessment of and recommendations on remote monitoring programs for patients with cardiac conditions is the first CADTH project to incorporate a realist review into the Health Technology Assessment. Learn more.