Byrne 2005 (Continued)
Risk of bias
Bias :Random sequence generation (selection bias)
Authors' judgement :Unclear risk
Support for judgement :"Schools were selected to reflect socioeco nomic diversity across the city"
Classes within selected schools randomised to one of three intervention programmes No method of randomisation stated No controls within selected schools. Con- trol group from previous study.
Clusters: Schools
Cluster constraint: Not stated
Baseline comparability: No significant dif- ferences in smoking rates at baseline be- tween groups. Classes did not differ on gen der and had representations in classes from all age groups in the school (intervention)