Hodder 2017.

Study characteristics
Methods	Trial name: effectiveness of a pragmatic school based universal resilience intervention in reducing tobacco, alcohol and illicit substance use in a population of adolescents Study design: cluster‐RCT Intervention duration: 3 years Length of follow‐up from baseline Baseline: August–November 2011 Follow‐up: July–November 2014 Differences in baseline characteristics: there was no difference for any of the demographic characteristics Unit of allocation Schools Unit of analysis Implementation outcomes: schools (clusters) Behavioural/health outcomes: student (individual)
Participants	School type: government or Catholic secondary school located in socioeconomically disadvantaged local government areas: year 7 at baseline, year 10 at follow‐up Region: 1 health district of NSW, Australia. Approximately 114,000 people aged 10–19 years resided in metropolitan, regional, rural and remote areas within the district. Demographics/socioeconomic characteristics Low SES status (< 990): intervention 55.6% students, control 59.5% students High SES status (> 990): intervention 44.4% students, control 40.5% students Remoteness (c) major city: intervention 39.1% students; control 47.1% students Remoteness (ARIA) Inner regional: intervention 29.7% students; control 32.1% students Remoteness (ARIA) Outer regional/remote: intervention 31.2% students; control 20.8% students Aboriginal/Torres Strait Islander: intervention 12.8% students, control 12.6% students Other ethnicity: intervention 12.3% students, control 7.9% students Inclusion/exclusion criteria Inclusion ‐ Government or Catholic secondary school located within a socioeconomically disadvantaged local government area ‐ Had enrolments in grades 7–10 (aged 12–16 years) ‐ Had > 400 total student enrolments Exclusion: ‐ Single gender schools ‐ Independent (private) ‐ Special educational needs ‐ Selective, central (for students aged 5–18 years) or boarding schools Number of schools allocated Schools:32 schools (20 intervention, 12 control) Students:4589 students (2823 intervention, 1766 control) (note, actually consenting students = 1909 intervention, 1206 control = 3115 total) Numbers by trial group n (controls baseline) = 12 schools, 1206 students n (controls follow‐up) = 12 schools, 844 students n (interventions baseline) = 20 schools, 1909 students n (interventions follow‐up) = 20 schools, 1261 students Recruitment Schools:eligible schools were approached in random order until a quota of 32 schools consented. Consenting schools were stratified according to participation in a government disadvantaged schools initiative (yes/no) and school size (medium 400–800/large > 800). Students:all students enrolled in grade 7 (first year at secondary school) and were eligible to participate in data collection. Active parental consent for student participation was sought via a mailed study information pack. A free call number was provided for parents who wished to decline. After 2 weeks, non‐responding parents were prompted via telephone by school‐affiliated staff who were blind to group allocation. Recruitment rate Schools:73% Students:67.9% of enrolled students, and 88.2% of students with parental consent
Interventions	Number of experimental conditions: 2 (1 intervention group; 1 usual care group) Policies, practices or programmes targeted by the intervention Increase protective factors for alcohol consumption, which included: ‐ Age‐appropriate lessons (9 hours) on individual protective factors across school subjects ‐ Non‐curriculum programmes (9 hours) targeting protective factors ‐ Additional programme targeting protective factors for Aboriginal students ‐ Rewards and recognition programme ‐ Peer support/peer mentoring programmes ‐ Antibullying programmes ‐ Empowerment/leadership programmes ‐ Additional empowerment/leadership/mentoring programmes for Aboriginal students ‐ Aboriginal cultural awareness strategies ‐ Promotion/engagement of local community organisations/groups/clubs in school (e.g. charity organisations) ‐ Additional/enhanced consultation activities with Aboriginal community groups ‐ Promotion/engagement of health, community and youth services in the school ‐ Additional/enhanced Aboriginal community organisations promoted or engaged ‐ Referral pathways to health, community and youth services developed and promoted ‐ Strategies to increase parental involvement in school (e.g. school events) Implementation strategies EPOC: educational outreach visits ‐ Strategy review workshops. EPOC: educational meetings ‐ Engagement with school community including presentations at school staff meetings regarding planned intervention; and staff mental health training. EPOC: local consensus processes ‐ School intervention team formed EPOC: educational materials ‐ Implementation guide, resources and programmes, and tool and templates. EPOC: external funding ‐ AUD2000 per year EPOC: audit and feedback ‐ Feedback reports termly Theoretical underpinning ‐ Of the evidence‐based intervention/policy/practice or programme: not reported ‐ Of the implementation strategy: not reported Description of control: control schools implemented usual school curricula and policies which may have included protective factor strategies and resources similar to, or the same as, those systematically provided to the intervention schools, but were not provided with programme resources or support. A report describing baseline school‐level student substance use and protective factor characteristics was provided to control schools.
Outcomes	Outcome relating to the implementation of school policies, practices or programmes: implementation of strategies targeting protective factors Data collection method: to assess intervention implementation by intervention schools, research staff reviewed school documents and recorded the delivery of intervention strategies monthly. In addition, at follow‐up, telephone‐based structured interviews were conducted with staff from both groups by interviewers regarding school implementation of intervention strategies and engagement with the intervention during the final year of intervention, school staff from intervention schools were asked their level of engagement with the intervention in the final year. Validity of measures used: not reported Outcome relating to cost: not reported Outcome relating to adverse consequences: not reported Outcome relating to child diet, PA or weight status: tobacco, alcohol, marijuana or other drug use, student and environment protective factors score Data collection method: substance‐use outcome data were collected using items from an ongoing Australian triennial survey of school students' health behaviours. Primary outcomes included tobacco use (ever and recent) alcohol (ever, recent and 'risky') use. Secondary outcomes included marijuana and other illicit substance use. The Resilience and Youth Development module of the California Healthy Kids Survey was used to measure individual and environmental protective factors. Validity of measures used: not reported
Notes	Research funding: National Health and Medical Research Council, nib Foundation and Hunter New England Population Health and infrastructure support from the Hunter Medical Research Institute. Conflicts of interest: no competing interests declared.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Primary outcome: then randomly allocated to intervention or control in a 20:12 block design ratio by an independent statistician using a random number function in Microsoft Excel prior to baseline data collection.
Allocation concealment (selection bias)	Unclear risk	Primary outcome: low risk, due to completion by trained statistician. However, the trial registration stated it was open with no blinding and, therefore, this was rated unclear.
Blinding of participants and personnel (performance bias) Implementation outcome	High risk	Primary outcome: high as schools/teachers were aware of group allocation.
Blinding of outcome assessment (detection bias) Implementation outcome	High risk	Outcome group: self‐report considered high risk. Outcome group: objective measures. Unclear: unclear if project staff who conducted secondary outcome analysis were blind to assessment (unlikely given the nature of the study).
Incomplete outcome data (attrition bias) Implementation outcome	Low risk	Primary outcome: all schools participated in follow‐up data collection, therefore, low risk. Outcome group: student behavioural outcome Low: loss to follow‐up > 20%; however, loss to follow‐up are explained and reasonable. Outcome group: staff interview. Low: loss < 20%.
Selective reporting (reporting bias)	High risk	Protocol manuscript available. Implementation costs not reported. PA, fruit and vegetable consumption, sexual activity student outcomes not reported (from trial registry).
Other bias	Unclear risk	Unclear if at risk of contamination. Appeared free of other biases.
Recruitment to cluster	Unclear risk	Unclear if students recruited prior or after cluster randomisation occurred.
Baseline imbalance	Unclear risk	Primary outcome: consenting schools were stratified according to participation in a government disadvantaged schools initiative (yes/no) 71 and school size (medium 400–800/large > 800). However, table 1 showed differences between school characteristics, and it was unclear in the analysis if these were adjusted for.
Loss of cluster	Low risk	Primary outcome: no loss of clusters, all schools completed baseline and follow‐up data collection.
Incorrect analysis	Unclear risk	No statement regarding clustering for implementation outcome. Reports Chi2 and t‐test analyses used to determine differences between schools.
Compatibility with individually randomised RCTs	Unclear risk	No statement regarding this.
Overall risk of bias assessment	Unclear risk	Most domains were at unclear risk of bias.