Toward the effective and efficient measurement of implementation fidelity.

Implementation science in mental health is informed by other academic disciplines and industries. Conceptual and methodological territory charted in psychotherapy research is pertinent to two elements of the conceptual model of implementation posited by Aarons and colleagues (2010)--implementation fidelity and innovation feedback systems. Key characteristics of scientifically validated fidelity instruments, and of the feasibility of their use in routine care, are presented. The challenges of ensuring fidelity measurement methods are both effective (scientifically validated) and efficient (feasible and useful in routine care) are identified as are examples of implementation research attempting to balance these attributes of fidelity measurement.