Piper 2000 (HFL).

Methods	Country: USA Site: Suburbs, small towns and rural areas in Wisconsin 'Healthy for Life Project' (HFL) Design: Cluster RCT (Group 1: never smoking prevention cohort)
Participants	Baseline: 2483 Age: 6th grade (68% 14yrs, 29% 15yrs) Gender: 52% F Ethnicity: % white: intervention 1 (HFL) N = 758 (92%), intervention 2 (HFL age appropriate) N = 827 (94%), control N = 898 (94%) Baseline smoking data: past month cigarette use: intevention 1 = 4%, intervention 2 = 5%, control = 5%
Interventions	Category: Multimodal vs. multimodal vs. control Programme deliverer: community adults (received conventional Project ALERT training), teens (school selected, 1‐day training by researchers, state cooperative extension educators, and adult program leaders) Intervention: the curriculum used 8 strategies: social inoculation; peer leaders; parent interviews; health advocacy; short‐term effects; advertising and media; public commitments; peer norms. Included peer, family and community components Healthy for Life curriculum (HFL) (Intensive Condition) targeted 5 health behaviours: alcohol, tobacco, marijuana, nutrition, and sexuality in 54 lessons in 12 wks in the 7th grade HFL Age Appropriate curriculum taught 58 lessons in 3, 4wk segments in each of grades 6, 7, and 8; Control: "usual programming, often included prevention oriented curricula such as Quest, Choices, Here's Looking at You, 2000 or locally developed curricula."
Outcomes	Annual self reported smoking status; saliva samples collected but not analysed Follow‐up: Grade 9
Notes	Quality of intervention delivery: "extensive qualitative data indicate positive reception of the program by the participating students", and that: "implementation fidelity was not a problem " but provided no documentation. The authors also commented that the teaching techniques were not commonly used by teachers and would have needed additional resources to sustain them Statistical quality: Was a power computation performed? Power computation calculation was that 6 schools per condition were needed with average enrolment of 200 students per school to detect a 20% reduction in tobacco use; achieved needed sample size of schools. Was an intention‐to‐treat analysis performed? Not stated Was a correction for clustering made? No Were appropriate statistical methods used? Parametric ANCOVA , with school level differences in substance abuse and health risk behaviours as covariates; hierarchical linear modelling with the HLM/3L programme; hierarchical multilevel regression models; and school level models controlled for multiple levels.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The original design proposed a stratified random assignment of schools to one of the three conditions. However, in recruiting schools for the project, it became apparent that most interested schools could not accommodate the fully randomised design, largely due to scheduling constraints which dictated choice of either the Intensive or Age Appropriate versions. Possible assignment to the control condition was seldom problematic... A two‐step procedure was implemented which allowed schools to select either the Intensive or Age Appropriate condition, with the understanding that random assignment to the control condition or the selected treatment condition would occur... Schools selecting each condition were separately stratified in groups of three into high, medium and low levels of substance use (among the existing student bodies ‐ cohorts older than the HFL students). The schools were then randomly assigned from these strata..." Email from Dr Moberg 20 February 2012 ‐ "numbers out of a bowl" Clusters: schools Cluster constraint: stratified in groups of three into high, medium and low levels of substance use. Baseline comparability: the groups were equivalent at baseline.
Allocation concealment (selection bias)	Unclear risk	No statement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No statement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1,981 students provided data in both 6th and 9th grade (80%), and 68% in both 6th and 10th grade (because were unable to schedule in school surveys of two Intensive and one control school). No attrition analysis
Selective reporting (reporting bias)	Low risk	No selective reporting