Australian secondary school students' use of tobacco, alcohol, and over-the-counter and illicit substances in 2011
2.1 Sample selection
The target population was all students in Years 7 to 12 across Australia. Population estimates were based on the most up-to-date figures available from state and federal education departments at the time. Schools with fewer than 100 students enrolled were excluded from the study.
Within each state and territory, schools were sampled using a random sampling methodology designed to represent students from the three main education sectors: government, Catholic and independent. The basic design of the sampling procedure was a stratified two-stage probability sample, with schools selected at the first stage of sampling, and students selected within schools at the second stage of sampling. Within each state and territory, schools were stratified by the three education sectors and randomly selected from each sector to ensure that the distribution of schools in the three education sectors was reflected in the sample. Two samples of schools were drawn to reflect the distinction between junior secondary (up to Year 10) and senior secondary (Years 11 and 12) campuses.
The study aimed to survey students from 414 schools across the country. To achieve this, 893 secondary schools were approached to take part in the study. Three hundred and sixty-three secondary schools participated in the study, giving an overall response rate for secondary schools of 41%. This was lower than the response rate achieved in 2008 and 2005. In South Australia and Queensland, Year 7 students are generally still in the primary school system. Therefore, primary schools associated with participating secondary schools in
these states were approached regarding the surveying of Year 7 students.
All surveying took place in the 2011 academic school year.