The User-Program Interaction: How Teacher Experience Shapes the Relationship Between Intervention Packaging and Fidelity to a State-Adopted Health Curriculum.

Intervention effects observed in efficacy trials are rarely seen when programs are broadly disseminated, underscoring the need to better understand factors influencing fidelity. The Michigan Model for Health™ (MMH) is an evidence-based health curriculum disseminated in schools throughout Michigan that is widely adopted but delivered with limited fidelity. Understanding implementation determinants and how they influence fidelity is essential to achieving desired implementation and behavioral outcomes. The study surveyed health teachers throughout Michigan (n = 171) on MMH implementation, guided by the Consolidated Framework for Implementation Research. We investigated relationships between context, intervention and provider factors and dose delivered (i.e., the proportion of curriculum delivered by teachers), a fidelity dimension. We also examined whether intervention factors were moderated by provider factors to influence fidelity. Our results indicated that program packaging ratings were associated with dose delivered (fidelity). We also found that this relationship was moderated by teacher experience. The strength of this relationship diminished with increasing levels of experience, with no relationship among the most experienced teachers. Intervention adaptability was also associated with dose delivered. We found no association between health education policies (context), provider beliefs, and dose delivered. Intervention factors are important determinants of fidelity. Our results suggest that providers with more experience may need materials tailored to their knowledge and skill level to support materials' continued usefulness and fidelity long-term. Our results also suggest that promoting adaptability may help enhance fidelity. Implementation strategies that focus on systematically adapting evidence-based health programs may be well suited to enhancing the fidelity of the MMH curriculum across levels of teacher experience.