It’s a bird, it’s a plane, it’s … fidelity measurement in the real world.

In psychotherapy research, fidelity instruments were originally developed as manipulation checks in experimental tests of treatment efficacy. The purposes of fidelity measurement are expanding as consumers, administrators, and payers seek to determine the extent to which the interventions purchased are actually received. Emerging purposes for fidelity measurement are described, as are challenges to developing a single instrument that can adequately meet multiple purposes, and that is both effective (psychometrically sound) and efficient (feasibly used in routine care). Examples are provided of efforts to balance these attributes of fidelity measurement, to measure fidelity at multiple levels of the practice context, and to index and evaluate the effects of additional program parameters on client outcomes in routine care.