The aims of this study were to determine (1) the degree to which an evidence-based intervention (EBI) delivered outside the context of a research trial remained faithful to the content and design of the programme as intended and as reported in experimental trials of the same programme, and (2) whether implementation quality affected programme outcomes. We report results of an observational study of 11 sites involved in the statewide dissemination of a popular family-focused prevention programme, the Strengthening Families Programme for Parents and Youth 10-14. We found numerous differences between the community-based implementations we observed and researcher-driven implementations of the same programme, but variability in programme delivery and adherence to content were unrelated to programme outcomes. We conclude that short-term outcomes of well-designed EBIs delivered by well-trained facilitators may be robust to minor changes in delivery and content. However, the effects of implementation quality on longer-term outcomes are unknown.
Keywords: Translational research; evidence-based interventions; implementation; programme fidelity; substance-abuse prevention.