A cluster randomised effectiveness-implementation trial of an intervention to increase the adoption of PAX Good Behaviour Game, a mental health prevention program, in Australian primary schools: Study protocol.

Introduction: Implementation of evidence-based programs in school settings can be challenging, undermining the benefits these programs deliver for children. The primary aim of this study is to assess whether an enhanced implementation intervention increases adoption of the PAX Good Behaviour Game in New South Wales (NSW) primary schools in Australia. A secondary outcome is to investigate the impact of the PAX Good Behaviour Game on children's mental health in the Australian context. Methods and analysis: The study uses a cluster randomised hybrid type 3 effectiveness-implementation design and will involve 40 NSW primary schools. Randomisation will occur at the school level. All NSW primary schools trained in the PAX Good Behaviour Game are eligible for participation. The intervention is a multicomponent implementation strategy that has been iteratively co-designed by our research team and local stakeholders. Intervention schools will have access to eight implementation support strategies in addition to the training received as usual delivery to build knowledge and skills. Research staff will assess implementation and effectiveness outcomes using self-report online surveys with teachers and support staff at baseline, 6-weeks, 6-months and 12-months follow up. Semi-structured interviews with teachers and support staff will be used to examine which implementation strategies worked for whom and under what conditions. Discussion: If successful, this study will highlight effective strategies schools or education departments can use internationally to improve their translation of evidence-based programs into routine practices. This will lead to better outcomes for children and young people.