Understanding and Quantifying the Scale-Up Penalty: a Systematic Review of Early Developmental Preventive Interventions with Criminological Outcomes

Purpose This article reviews the process of scaling up early developmental preventive interventions with criminological outcomes over the life-course, with a focus on quantifying the scale-up penalty. The scale-up penalty is an empirically based quantification of the amount of attenuation in the effects of interventions as they move from research and demonstration projects to large-scale delivery systems attempting to achieve population-level impacts. Methods Asystematic review was conducted, which included rigorous criteria for inclusion of studies, comprehensive search strategies to identify eligible studies, and a detailed protocol for coding key study characteristics and factors related to the scale-up penalty. Results A total of six studies met the inclusion criteria, originating in two countries (USA and Norway) and covering a 20-year period (1998 to 2017). Studies showed large variability in the scale-up penalty assigned, ranging from 0 to 50%, with one study reporting scale-up penalties from negative to 71%. A wide range of factors were considered in quantifying the scale-up penalty, including implementation context, heterogeneity in target populations, heterogeneity of service providers, and fidelity to the model. The most recent studies were more comprehensive in their consideration of factors influencing the scale-up penalty. Conclusions It is important for program developers and policymakers to recognize and account for implementation challenges when scaling up early developmental preventive interventions. Further research in this area is needed to help mitigate attenuation of program effects and aid public investments in early developmental preventive interventions.