ABSTRACT
In this chapter, we discuss intervention fidelity, or administration quality, as a key factor in supporting treatment effectiveness when programs are brought to scale. Intervention dosage can be challenged by properties of the scale-up situation, but strong fidelity enhances client engagement and reduces dropout, in turn improving intervention outcomes. The chapter describes several challenges to maintaining fidelity when interventions are brought to scale, such as issues related to measurement (e.g., how is fidelity defined and measured in a way that is scalable?), practitioner selection (e.g., how are practitioners screened and selected with an eye toward fidelity?), and training and support (e.g., what type and level of support is needed to ensure that fidelity criteria are met and sustained?). We explore these issues using an example from the early childhood intervention field, Attachment and Biobehavioral Catch-up (ABC), a 10-session, home-based parent coaching intervention for infants and toddlers. ABC model developers created fidelity assessment and support procedures that consider many of these issues and have been scalable. In this case example, we describe how fidelity issues were addressed when ABC was scaled by Power of Two, a nonprofit organization in New York City. We end by offering recommendations and future directions for stakeholders, including researchers, model developers, policy makers, funders, and heads of agencies.
