Background: Determining the success of population health interventions often involves assessing multiple, multidimensional outcomes rather than a single one, which presents significant methodological challenges under the evidence-based medicine paradigm. This scoping review examines outcome selection, analysis, and interpretation, and the accuracy of conclusions in complex digital health interventions promoting health among adolescents and young adults (DHI-AYA). Methods: A comprehensive search of PubMed, EMBASE, ClinicalTrials.gov, PsycINFO, and CINAHL identified DHI-AYA implemented between 2017 and 2023. Studies were categorised by methodological choice regarding outcome hierarchical position: unique primary, multiple primary, or non-hierarchised outcomes. Outcomes were further classified into effectiveness, process, or economic categories. The authors’ conclusions on intervention success were compared with conclusions drawn by the research team based on the reported outcome analysis strategy. Secondly, four analytical strategies were applied to a subset of selected interventions to illustrate the impact of outcome hierarchical position and number on conclusions about intervention success. Results: Analysis of 100 studies linked to 26 DHI-AYA identified 251 distinct outcomes: 164 effectiveness, 78 process, and 9 economic outcomes. Seven interventions were evaluated using a unique primary outcome, 10 using multiple primary outcomes, and 9 using multiple non-hierarchised outcomes. Primary and secondary outcomes were predominantly effectiveness endpoints. The research team reclassified nine interventions (35%) deemed successful by authors as non-conclusive due to statistically conflicting results across outcomes. Most interventions deemed non-conclusive by the research team were evaluated using non-hierarchised outcomes (7/10, 70%). The choice of outcome analysis strategy substantially affected conclusions on intervention success. Conclusions: Discrepancies in intervention success assessments highlight the need for enhanced transparency, robustness, and trustworthiness in conclusion-drawing processes. In response, five methodological proposals are formulated: (1) developing core outcome sets specific to population health intervention research (PHIR), (2) collaboratively selecting multidimensional outcomes through a steering committee that accounts for stakeholder preferences and existing theoretical models, (3) exploring multi-criteria decision analysis and consensus-driven methods to transparently combine outcomes, (4) enhancing methodological reporting through intervention development and evaluation to improve scientific integrity and reproducibility, and (5) increasing PHIR expert involvement in ethics, funding, and evaluation committees to improve recognition of evidence produced in this field. PROSPERO Registration number: CRD42023401979.

Face washing for trachoma, like most public health improvements, necessitates behaviour change, yet traditional educational interventions frequently fail to achieve this goal. Behavioural science frameworks offer guidance to develop alternative types of interventions, helping to translate formative research and insights about the target population and behavioural determinants into more effective strategies. This paper outlines the outputs and decision-making underlying the five-stage process we followed to translate formative research findings into intervention activities and materials: (1) synthesising formative research findings into a creative brief to guide intervention development; (2) selecting behaviour change techniques (BCTs) to address key behavioural targets; (3) selecting an overarching intervention concept; (4) developing intervention content; and (5) finalising the intervention’s Theory of Change. This paper presents our experiences and reflections on the intervention design process, using a practical example of a face washing intervention for trachoma control. The intervention was designed for delivery in the Stronger SAFE trial in rural Oromia, Ethiopia (ISCRTN 40760473).

Considérations méthodologiques pour l'évaluation des interventions de promotion de la santé : éclairages issus de programmes numériques destinés aux jeunes: Les interventions de promotion de la santé visent à agir sur les déterminants sociaux, environnementaux et politiques de la santé afin d'autonomiser les individus, de favoriser des comportements favorables à la santé et de réduire les inégalités. Ces interventions sont généralement conceptualisées comme des interventions complexes, comprenant de multiples composantes interagissant à différents niveaux et dont les effets sont façonnés par les contextes de mise en œuvre. L'évaluation d'une telle complexité nécessite des approches méthodologiques capables de saisir la multiplicité des effets, l'influence des contextes et les effets non intentionnels ; des défis qui continuent d'alimenter un débat méthodologique important. Si les essais contrôlés randomisés demeurent largement considérés comme la référence pour l'évaluation des interventions en santé, leur capacité à refléter la complexité, la dynamique contextuelle et la multidimensionnalité des effets propres aux interventions de promotion de la santé reste limitée. Le Medical Research Council Guidance for Developing and Evaluating Complex Interventions propose un cadre structurant en quatre phases de recherche (développement, faisabilité, évaluation et mise en œuvre), mais son opérationnalisation demeure difficile, en particulier pour la synthèse et l'interprétation des critères de jugement multiples. En prenant comme objet empirique les interventions de santé numérique destinées aux adolescents et aux jeunes adultes (DHI-AYA), un champ en pleine expansion dans la pratique de la promotion de la santé, cette thèse poursuit trois objectifs : (1) analyser les pratiques actuelles de structuration des programmes de recherche en promotion de la santé ; (2) examiner les approches méthodologiques utilisées pour mesurer et interpréter des critères de jugement multiples ; et (3) élaborer des recommandations fondées sur des données probantes pour une évaluation transparente, multidimensionnelle et robuste des interventions de promotion de la santé. Une revue systématique de 31 programmes DHI-AYA a mis en évidence une hétérogénéité importante des structures de programmes, une fréquence élevée des itérations et des chevauchements entre les phases, ainsi que des pratiques d'évaluation centrées principalement sur les effets d'efficacité, souvent au détriment de la transparence dans la sélection et l'interprétation des critères de jugement. À partir de ces constats, une étude de consensus multi-étapes, réunissant des experts français et européens, a permis d'identifier un ensemble de recommandations méthodologiques pratiques. Les experts ont souligné la nécessité de construire une preuve progressive et multidimensionnelle du « succès » des interventions, en reconnaissant que des études distinctes peuvent être requises à différentes phases de recherche et pour différents groupes d'acteurs. Ils ont plaidé pour un pluralisme méthodologique, combinant des données qualitatives et quantitatives, pour la prise en compte explicite des gradients socioéconomiques et des contraintes éthiques, ainsi que pour la reconnaissance des influences réglementaires, financières et politiques sur la conception des évaluations. Surtout, les participants ont affirmé que la prise de décision concernant les interventions devait être envisagée comme un processus inclusif, démocratique et intrinsèquement social, dépassant la seule expertise méthodologique des chercheurs. Les cadres opérationnels et recommandations pratiques issus de ce travail soulignent la nécessité de renforcer les pratiques de transparence et de développer des standards de recherche allant au-delà des paradigmes classiques des essais cliniques. De tels progrès sont essentiels pour produire des données probantes robustes et sensibles aux contextes, afin d'éclairer la prise de décision et de guider la mise en œuvre d'interventions promouvant l'équité en santé et la justice sociale.

Background: Depression and anxiety among youth have increased significantly, highlighting the urgent need to improve their mental health literacy. Gaming platforms, such as Twitch with nearly 100,000 weekly Minecraft streamers, offer significant potential as innovative venues for mental health promotion.Objective: To co-design, implement, and evaluate a Minecraft streaming-based intervention promoting mental health literacy among adolescents and young adults aged 15-25 years.Methods: Through participatory action research, we conducted ten virtual workshops (October 2023-June 2024) with four streamers and a clinical psychologist to co-develop "Walk Your Therapist"—live streams combining Minecraft gameplay with mental health education. We evaluated the intervention using a quasi-experimental design with the Mental Health Literacy Questionnaire (MHLq), observations, chat analysis, and interviews.Results: Three sessions reached 613 unique viewers. Of these, 97 participants completed baseline assessments (mean age 19±4 years, 86.6% male, 9.3% NEET) and 43 completed follow-up. Participants showed significant improvements in MHLq scores (94±19 to 104±7, p<.001, d=0.70), with gains in knowledge of mental health problems (38.2±9.3 to 44.2±4.9, p<.001), first aid skills (20.9±6.2 to 23.0±4.1, p=.04), and self-help strategies (16.1±3.2 to 17.2±2.2, p=.03). Participants spontaneously discussed gaming addiction and stigma. Streamers reported increased personal mental health awareness and sustained positive community engagement.Conclusion: This co-designed gaming intervention demonstrates promising potential for youth mental health promotion through existing streaming communities.Trial Registration: ClinicalTrials.gov NCT06473857

BACKGROUND Depression and anxiety among youth have increased significantly, highlighting the urgent need to improve their mental health literacy. Gaming platforms, such as Twitch with nearly 100,000 weekly Minecraft streamers, offer significant potential as innovative venues for mental health promotion. OBJECTIVE To co-design, implement, and evaluate a Minecraft streaming-based intervention promoting mental health literacy among adolescents and young adults aged 15-25 years. METHODS Through participatory action research, we conducted ten virtual workshops (October 2023-June 2024) with four streamers and a clinical psychologist to co-develop "Walk Your Therapist"—live streams combining Minecraft gameplay with mental health education. We evaluated the intervention using a quasi-experimental design with the Mental Health Literacy Questionnaire (MHLq), observations, chat analysis, and interviews. RESULTS Three sessions reached 613 unique viewers. Of these, 97 participants completed baseline assessments (mean age 19±4 years, 86.6% male, 9.3% NEET) and 43 completed follow-up. Participants showed significant improvements in MHLq scores (94±19 to 104±7, p<.001, d=0.70), with gains in knowledge of mental health problems (38.2±9.3 to 44.2±4.9, p<.001), first aid skills (20.9±6.2 to 23.0±4.1, p=.04), and self-help strategies (16.1±3.2 to 17.2±2.2, p=.03). Participants spontaneously discussed gaming addiction and stigma. Streamers reported increased personal mental health awareness and sustained positive community engagement. CONCLUSIONS This co-designed gaming intervention demonstrates promising potential for youth mental health promotion through existing streaming communities. CLINICALTRIAL ClinicalTrials.gov NCT06473857

BACKGROUND The UK Medical Research Council’s Guidance on Developing and Evaluating Complex Interventions (MRC GDECI) outlines a 4-phase framework for structuring research programs on interventions: development, feasibility, evaluation, and implementation. However, it provides limited practical direction on how researchers should select which phases to conduct or determine when and whether to progress between phases. This gap is particularly challenging in the context of digital health interventions (DHIs), given their fast-paced and rapidly evolving nature. OBJECTIVE This scoping review examined the research phases conducted, how researchers progressed through them, and the intervention characteristics associated with overall program structure and duration in DHI research, to inform the design of future research programs. METHODS We searched PubMed, Embase, CINAHL, PsycINFO, and ClinicalTrials.gov to identify complex DHIs promoting health among adolescents and young adults, implemented between 2017 and 2026, for which at least 2 phases of the MRC GDECI were reported, including the evaluation phase. For each eligible intervention, all related protocols, preprints, and published articles were retrieved to reconstruct the full research program. For each program, we analyzed the presence of each research phase, its organization (ie, phase arrangements), and the mechanisms guiding progression between phases (ie, progression mechanisms). Phase-specific and overall program durations were recorded. RESULTS A total of 31 research programs, covering 31 interventions and reported in 130 articles, were included. Development, feasibility, evaluation, and implementation phases were reported in 26, 23, 31, and 7 research programs, respectively. Three types of phase arrangements were identified: sequential, iterative, and overlapping. Progression mechanisms between phases included automatic progression, conditional progression based on researchers’ appraisal of findings without prespecified criteria, and progression based on predefined quantitative criteria. Six main research program structures were observed, combining phase arrangements and progression mechanisms. Iterative arrangements were most common, observed in 22 research programs, followed by overlapping (n=10) and strictly sequential structures (n=7). Most progressions relied on researchers’ appraisal of findings without prespecified criteria. Justifications for phase iteration, omission, or progression decisions were rarely reported. The median program duration was 5.8 (IQR 3.8-6.6) years (n=13). Based on these findings, a novel 4-step operational framework and visualization tools were developed to guide the design and planning of DHIs, highlighting key considerations for each step, as well as the strengths, limitations, and risks associated with each phase arrangement and progression mechanism. CONCLUSIONS This scoping review is the first to systematically examine phase arrangements and progression mechanisms in DHI research programs. Beyond descriptive reporting, it provides a conceptualization of research program structures and offers a flexible operational framework to support the concrete implementation of the MRC GDECI. Greater explicitness in decisions about program structure may enhance methodological rigor, reduce research waste, and improve the integrity and reproducibility of interventions. CLINICALTRIAL PROSPERO CRD42023401979; https://tinyurl.com/mvc265y3