Transferability of Interventions
The commitment to evidence-based policy and practice raises the question of how far evidence of effectiveness can be generalised from one setting to another, across target populations or between different problems. Policymakers and practitioners frequently have to decide whether an intervention developed for a different setting, target group and/or problem would be appropriate for their needs. Similarly, research funders have to decide whether further evaluation is required for interventions delivered in different circumstances.
These decisions are especially critical in low-income countries since:
- evidence of effectiveness for many interventions often comes predominantly from high income countries, with fundamentally different contexts
- resources for research are generally scarce, making it difficult to justify the confirmation of evaluations conducted elsewhere.
The outcomes of interventions come from the interaction between change mechanisms and their specific contexts, so it cannot be assumed that effective interventions can be transferred between different settings (whether different institutions, sectors or countries) and generate the same outcomes. Transferability will depend on which contextual factors and characteristics of the target group and problem are most important in shaping outcomes, and how far these factors vary between settings.
To date, there is no widely accepted framework for understanding transferability. Our aim is to establish whether one can formulate general principles about the transferability of interventions, by addressing the following questions:
- Which aspects of setting, target group or problem have insignificant impact on effectiveness?
- Which aspects of setting, target group or problem can be addressed through intervention adaptation without loss of effectiveness?
- What are the components of interventions that make them resilient to potential loss of effectiveness across setting, target group or problem?
Since understanding the specificity of evaluation evidence involves detailed knowledge of the interventions, their settings, target group and the problem being addressed, we have selected three case studies, each of which is relevant to an important policy area. These are early years parenting, problem drug use, and obesity and physical exercise.