Background. Earlier studies on risk factors of adolescent gambling and risk gambling have mainly focused on determinants at the individual or the family level. Yet, it is likely that also other social contexts in young people's lives affect their inclination to engage in gambling and in risk gambling. One such context is the school. The aim of the present study was to investigate the extent of between-school variation in gambling and in risk gambling, and to analyse the links between school collective efficacy and student gambling and risk gambling.

Methods. Data were derived from the Stockholm School Survey (SSS) and the Stockholm Teacher Survey (STS), conducted in 2016 among 5191 students and 1061 teachers in 46 upper secondary schools. School collective efficacy i.e. schools degree of social cohesion and informal control was assessed by teachers' responses to four items in the STS, which were added to an index and aggregated to the school level. Gambling and risk gambling were assessed by students' self-reports to four items in the SSS. Official register information on schools was also added to the data. Two-level binary logistic regression analyses were performed.ResultsResults show statistically significant between-school variation in both gambling (ICC=8.3%) and in risk gambling (ICC=18.1%). Compared with students attending schools with weak collective efficacy, those attending schools with strong collective efficacy were less likely to report both gambling (OR 0.58, 95% CI 9,40-0.82) and risk gambling (OR 0.40, 95% CI 0.22-0.71), even when adjusting for student- and school-level sociodemographic characteristics.

Conclusions. Students' inclination to engage in gambling and in risk gambling varies across schools. The findings suggest that a high level of school collective efficacy may contribute to counteract students' engagement in gambling and risk gambling.

Key messages. Students’ inclination to engage in gambling and in risk gambling varies across schools.The findings indicate that a strong school collective efficacy may contribute to reducing students’ inclination to engage in health risk behaviours.