Precision Implementation: An Approach to Mechanism Testing in Implementation Research.

Advancing mechanism-focused research in implementation science is a priority given its potential to improve tailoring and efficiency of implementation strategies. Experimental therapeutics, or experimental medicine, offers an approach for mechanism testing that has been promoted by the NIH Science of Behavior Change and endorsed by the National Institute for Mental Health. This approach has been applied across the translational spectrum - with initial applications to biological research and more recent applications to psychosocial treatment development research. We describe further advancement of experimental therapeutics along the translational spectrum and describe how it is ideally suited to inform precision experimental tests of implementation strategy mechanisms, which we term precision implementation. Such an approach to mechanism testing will allow for identification of causal dose-response relationships between implementation strategies, presumed mechanisms, and implementation outcomes. We discuss the tension between the scientific rigor required to conduct mechanism-focused research using experimental therapeutics and the "real world" conditions in which implementation research takes place. We provide a series of example studies that show "beginning to end" application of this framework in research focused on provider implementation of an evidence-based intervention in routine clinical care settings.