A mixed methods investigation of implementation determinants for a school-based universal prevention intervention.

Background: Effective implementation of evidence-based prevention interventions in schools is vital to reducing the burden of drug use and its consequences. Universal prevention interventions often fail to achieve desired public health outcomes due to poor implementation. One central reason for suboptimal implementation is the limited fit between the intervention and the setting. Research is needed to increase our understanding of how intervention characteristics and context influence intervention implementation in schools to design implementation strategies that will address barriers and improve public health impact. Methods: Using a convergent mixed methods design we examined qualitative and quantitative data on implementation determinants for an evidence-based health curriculum, the Michigan Model for Health Results: We identified three mixed methods domains: (1) Acceptability, (2) intervention-context fit, and (3) adaptability. We found alignment across data strands as teachers reporting low acceptability also reported low fidelity. The fit between student needs and the curriculum predicted fidelity (expansion). Teachers mentioned instances of poor intervention-context fit (discordance), including when meeting the needs of trauma-exposed youth and keeping updated on youth drug use trends. Teachers reported high adaptability (concordance) but also instances when adaptation was challenging (discordance). Conclusions: This investigation advances implementation research by deepening our understanding of implementation determinants for an evidence-based universal prevention intervention in schools. This will support designing effective implementation strategies to address barriers and advance the public health impact of interventions that address important risk and protective factors for all youth. Plain Language Summary: (1) What is Already Known About the Topic? While many evidence-based interventions (EBIs) exist to address key health issues among youth including substance use and mental health, few of these interventions are effectively implemented in community settings, such as schools. Notable multilevel barriers exist to implement universal prevention in schools. Researchers identify that misalignment between the intervention and the context is a key reason why many implementation efforts do not achieve desired outcomes. (2) What Does This Paper Add? This paper combines the strengths of qualitative and quantitative research methods to identify and understand challenges to intervention-context fit for a comprehensive health curriculum, the Michigan Model for Health