Process evaluation of a digital school-based intervention: lessons learned from the Health4Life study.

BACKGROUND: Process evaluations of preventive health interventions are essential for enhancing their implementation and impact. PURPOSE: This study presents the process evaluation of Health4Life, a digital school-based program designed to modify multiple health risk behaviors among adolescents. METHODS: Data were derived from a cluster randomized controlled trial in 71 Australian secondary schools from 2019 to 2022, including data from 2085 students and 118 teachers. Based on the Medical Research Council guidance for process evaluations this study explored three key questions: (i) Was the Health4Life intervention delivered and received as intended? (ii) How did participants respond? and (iii) What contextual factors influenced implementation? Fidelity, dose and exposure to intervention components were assessed through teacher self-report and website analytics. Participant responsiveness included student and teacher acceptability, and factors associated with a positive program evaluation (i.e. students' ratings of enjoyment, relevance, and utility). Contextual factors relating to schools and the intervention were assessed via teacher-reported open-ended feedback. The Consolidated Framework for Implementation Research (CFIR) was applied to support interpretation of findings. RESULTS: Fidelity to the online modules was high based on teacher self-report, but the dose received by students was moderate (62% full dose), and use of the supplementary components varied. Program acceptability was high, with most students (73%) and teachers (84%) rating Health4Life favorably overall. Key factors associated with a positive student evaluation were identifying as female, and having higher baseline knowledge of health risk behaviors, greater self-control and higher socioeconomic advantage. Qualitative data identified key contextual barriers and facilitators relating to program design, technology and school contextual issues. CONCLUSIONS: These findings provide valuable insights to support the ongoing refinement and broader implementation of Health4Life. A set of recommendations are proposed to inform the future development, implementation, and evaluation of digital health interventions in school environments. CLINICAL TRIAL INFORMATION: The Health4Life study was pre-registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619000431123).