1. Self reported ever, past month and weekly smoking, 2. Saliva samples collected, and analysed for a random sample of 654 (only 3 (0.5%) of the 560 who reported not smoking in the prior month or 2 days had saliva cotinine concentrations 10ng/ml: 1.7% gave inconsistent responses at baseline :1.5% at follow- up, and 6.59% across waves) Follow-up: 8 to 10th grade.