Setting, survey participants, sample selection and recruitment

This study is part of a larger project evaluating an Australian youth water safety drowning prevention program. This research was undertaken in Perth, the state capital of Western Australia (WA) on the west coast of Australia. WA is Australia’s largest geographical state with a population of 2,660,026 mainly residing along the coast [30]. The southwest coastal area (where Perth is located) has a temperate climate and summer occurs between the months of December–March [31]. A cross-sectional online survey was conducted at three time points (October 2019: T1; February 2020: T2 and March 2021: T3) with a convenience sample of young people. The criteria for inclusion were: English speaking, aged 15–24 years and residing in WA. The sampling protocol required 20% of participants to be from regional or remote WA, and 40% of the sample to be aged 15–19 years and 60% to be aged 20–24 years. Eligible participants were invited to complete an online survey using Qualtrics survey software (2017). An information sheet provided background to the study and the option to withdraw from the study at any point. Participants under 18 years were approved for mature minor informed consent by the University Human Research Ethics Committee (HREC). All participants were asked to indicate consent via an online question before they were able to proceed to the survey. The survey was distributed via networks of the WA peak, non-government drowning prevention organisation. Written informed consent was obtained electronically from all participants included in the study. The study was approved by the University Human Ethics Committee (Approval no. HR201/2014).