Adapted, Adopted, and Novel Interventions: A Whole-Population Meta-Analytic Replication of Intervention Effects

A challenge to implementation is management of the adaptation-fidelity dilemma or the balance between adopting an intervention with fidelity while assuring fit when transferred between contexts. A prior meta-analysis found that adapted interventions produce larger effects than novel and adopted interventions. This study attempts to replicate and expand previous findings. Meta-analysis was used to compare effects across a whole-population of Swedish outcome studies. Main and subcategories are explored. The 523 studies included adapted (22%), adopted (33%), and novel (45%) interventions. The largest effect was found for adapted followed by novel and adopted interventions. Interventions in the mental health setting showed the highest effects, followed by somatic healthcare and social services. These results replicate and expand earlier findings. Results were stable across settings with the exception of social services. Consistent with a growing body of evidence results suggest that context is important when transferring interventions across settings.