What is a Realist Literature Review?

Understanding how, why, and under what circumstances complex interventions work is crucial for making informed decisions and policies. Realist reviews offer a robust methodology to achieve this by focusing on the mechanisms, contexts, and outcomes of interventions. They delve deeper to explore the intricate dynamics that contribute to an intervention's success or failure.

Realist reviews, also known as realist syntheses, are a type of literature review that aims to explain how and why interventions, such as complex policy interventions, work in specific contexts. They focus on the underlying mechanisms of action, the contexts in which these mechanisms operate, and the outcomes they produce. The primary purpose of a realist review is to provide a nuanced understanding of the complex interactions between interventions and their contexts. Realist reviews seek to answer questions such as: What works for whom, in what contexts, and why? How do specific contexts influence the effectiveness of interventions? What are the key mechanisms that drive outcomes? It is rooted in realist philosophy, which emphasizes the importance of understanding the mechanisms through which interventions bring about outcomes and the contextual factors that influence these mechanisms.

These reviews help policymakers, practitioners, and researchers determine the effectiveness of an intervention and understand the conditions under which it can be most effective. Realist review methodology is designed to develop and refine program theories that explain the observed outcomes. These program theories explain how an intervention works in different contexts, and researchers can explore the particular mechanisms that generate outcomes while considering the influence of contextual factors.

Realist reviews are grounded in theories that explain how interventions are supposed to work. These theories are tested and refined throughout the review process. A central element of realist reviews is the identification of Context-Mechanism-Outcome configurations (Pawson and Tilley 1997). These configurations help explain how certain contexts trigger specific mechanisms, leading to particular outcomes. The review process is iterative, involving constant refinement of theories and conclusions as new evidence is analyzed. Realist reviews emphasize understanding causal relationships rather than merely identifying correlations between interventions and outcomes.

When to conduct a realist review?

Conducting a realist review is particularly advantageous when dealing with complex interventions involving multiple components and interactions. These interventions often do not yield straightforward results, and a realist synthesis can uncover the underlying mechanisms driving outcomes. This approach is especially useful in fields like healthcare, education, and social policy, where numerous factors interplay. When interventions are applied across diverse contexts, a realist review helps explain how different settings influence outcomes. If an intervention works well in one context but not in another, a realist synthesis can identify the contextual factors that affect its success or failure.

Realist reviews are also appropriate when there is a need to develop or refine theoretical frameworks explaining how interventions work. This theory-driven inquiry is beneficial in building a robust understanding of the underlying principles guiding effective interventions. When stakeholders need practical insights for program implementation or policy development, a realist review provides detailed explanations of what works, for whom, and under what circumstances. This type of review is valuable for policymakers, program developers, and practitioners requiring actionable knowledge. Lastly, in situations with limited or fragmented evidence, a realist review can synthesize available data to provide a coherent understanding of intervention mechanisms and contexts.

How are realist reviews different from other reviews?

A realist review or realist synthesis, differs notably from conventional review methodologies, such as those used in systematic reviews and meta-analyses. A systematic review designed to assess the effectiveness of interventions primarily uses quantitative methods to aggregate findings across studies. This approach focuses on producing a summary of evidence to determine if an intervention works. In contrast, realist syntheses aim to uncover the underlying mechanisms and contextual factors influencing outcomes. Unlike systematic reviews, which often provide little or no clue about how or why an intervention works, realist reviews explore these dynamics in-depth, offering a richer understanding of the intervention's impact within specific settings.

In the health sciences, where the complexity of interventions is often high, realist syntheses offer a unique advantage. While systematic reviews provide valuable insights into the overall effectiveness of interventions, they do not delve into the intricacies of programme theory. Realist reviews, guided by realist program theory, examine the interactions between context, mechanism, and outcome, offering a comprehensive view of how interventions work. This approach contrasts with the conventional review methodology, which may overlook these critical factors. By focusing on the realist program theory, realist syntheses provide practical insights that can inform the design and implementation of interventions, particularly in complex fields like health sciences.

How to conduct a realist review?

Conducting a realist review involves several key steps to ensure a thorough and systematic approach to understanding complex interventions. Here are the main steps:

1. Formulate the review question: Define the review question, objectives, and scope. This question should incorporate elements of context, mechanism, and outcome (CMO)(Pawson and Tilley 1997). The review focus should be on theory development and refining theory through empirical evidence and qualitative data.

2. Search for evidence: Conduct an iterative and flexible search process to gather a wide range of evidence. This includes primary studies and meta-narrative evidence syntheses that can provide insights into how the intervention works in different settings.

3. Appraise and extract data: Evaluate the relevance and rigour of the research evidence. Focus on extracting data that illuminate the mechanisms, contexts, and outcomes related to the intervention. Use inclusion and exclusion criteria to ensure the evidence is relevant to the review scope.

4. Synthesize evidence: Develop and refine theories about how the intervention works by identifying patterns across the studies. This involves constructing CMO configurations (Pawson and Tilley 1997) that explain the observed outcomes. Data synthesis is a crucial part of this process.

5. Interpreting and reporting: Interpret the findings to provide actionable insights. The final report should include recommendations on how the intervention can be adapted or improved based on the understanding of its mechanisms and contexts. Stakeholder involvement in this phase can enhance the practical relevance of the findings.

Conclusion

Conducting realist reviews offers a powerful approach to understanding the complexities of interventions in real-world settings. A realist review provides valuable insights that go beyond simple effectiveness, focusing on the interplay between context, mechanism, and outcome. This method is particularly beneficial in healthcare, education, social policy, and environmental initiatives, where understanding the contexts, mechanisms, and outcomes is crucial.

Realist reviews help design and implement interventions that are both effective and context-sensitive. They delve into the why and how behind outcomes, making them essential for developing evidence-based policy grounded in a deep understanding of real-world complexities.

Realist reviews use diverse evidence and explain variability in outcomes, enhancing our understanding of interventions and improving their practical application in real-world settings. As a result, they serve as an indispensable method for designing and implementing effective, context-sensitive interventions. Employing realist reviews in your research can lead to more impactful and sustainable solutions across various fields.

References

1. Pawson, R., & Tilley, N. (1997). Realistic Evaluation. SAGE Publications.