Evaluating complex interventions: Confronting and guiding (versus ignoring and suppressing) heterogeneity and adaptation
Brian S. Mittman, Ph.D.
Implementation strategies and many of the clinical and health service delivery interventions they aim to implement are characterized by multiple components targeting multiple behaviors and levels and are often characterized by extreme heterogeneity and adaptability. Although researchers often attempt to standardize and achieve fidelity to highly-specified manualized intervention protocols, the required actions to suppress adaptation and maximize internal validity often lead to reduced effectiveness: adaptation to local conditions often increases intervention effectiveness relative to implementation of a fixed version of an intervention across heterogeneous settings. This presentation introduces the new PCORI Methodology Committee Standards for Complex Interventions and discusses their role in research to (a) study and guide rather than suppress or ignore adaptation, achieving internal validity through adherence to an adaptation algorithm and through fidelity to function rather than form, and to (b) develop empirical evidence, insights and guidance for policy and practice decision makers who are charged with adapting and managing complex interventions rather than simply selecting and deploying simple, fixed interventions.