Elder 1996.

Methods	Country: USA Setting: schools RCT. Cluster randomisation by school
Participants	96 elementary schools in 4 states
Interventions	Trial of school‐based cardiovascular health promotion, including an intervention designed to limit child ETS exposure Intervention: consisted of promoting adoption of a formal tobacco‐free policy for the school and providing classroom‐ and home‐based programmes for students Control: Schools participated in the evaluation but received no recommendations for policy or for classroom‐ or home‐based interventions. Control schools were not restricted from taking up tobacco‐free policies.
Outcomes	At 2 years: • School principals (or delegates) were surveyed with respect to their school's policy on tobacco and the degree to which the policy was observed.
Type of intervention	Community‐based
Notes	Retention: 96/96; this is the CATCH study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Ten schools at each site were randomly assigned to the control condition and 7 schools each to a school‐based intervention (food service, physical education, classroom curricula) or the school‐based plus family intervention program"; no further information given
Allocation concealment (selection bias)	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	100% of third grade teachers and 67% of students attended Family Fun Nights; 100% of schools remained in the dietary assessment process.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not specified