The International Youth Development Study (IYDS) is a long-term study that looks at the development of healthy and problem behaviours among young people in the state of Victoria, Australia and the state of Washington, United States.
IYDS is one of the first studies designed to examine whether or not differences in Australian and American school policies affect youth development. The study began in 2002. The original sample included approximately 1000 students at each of three year levels in both Victoria and Washington, giving a total of nearly 6000 participants. The study continues to follow-up participants into young adulthood.
Study focus
Risk and protective factors, as well as healthy and problem behaviours in young people including substance use, delinquency, violence, risky sex, depression and self-harm.
Sampling frame
In 2002, a two-stage cluster sample design was used to recruit students in both states (Victoria, Australia and Washington State, USA). In the first stage, schools were selected at random, based on a probability proportional to grade-level size from a stratified sampling frame of all schools in Victoria (government, Catholic and independent) and Washington (public, private and alternative). At Stage 2, single intact classes from each school for the selected grade level (Grade 5 (Youngest), 7 (Middle) or 9 (Oldest)) were chosen at random; in a few cases, 2 classes from different year levels were randomly chosen at a school.
Data access
Data are available according to study protocols, namely: approval of proposal by Principal Investigators; Data Sharing Collaboration Agreement read and agreed to by all parties, Fair Use Agreement signed by applicant and Principal Investigators.
Time period
2002Original sample size
AUS: 2884, USA: 2885 (Total 5,769)Intergenerational
NoImaging
NoLinkage
NoBiosamples
NoEthics approvals or requirements
The IYDS has ethics approval through the following Human Research Ethics Committees - Royal Children’s Hospital (20086), University of Melbourne (060045X) and Deakin University (2007-136, 2018-096). This project only (Specific consent)Waves
| Wave | Year / Period | Age (mean, range) | Eligible sample |
|---|---|---|---|
| 1 | 2002 | AUS: 13, 9.8 – 16.5 (Y) (M) (O) USA: 13.1, 9.7 – 17.2 (Y) (M) (O) |
2884 (Y) (M) (O) 2885 (Y) (M) (O) |
| 2 | 2003 | AUS: 14, 11 – 17.4 (Y) (M) (O) USA: 14.1, 10.8 – 18.4 (Y) (M) (O) |
2884 (Y) (M) (O) 2885 (Y) (M) (O) |
| 3 | 2004 | AUS: 14, 11.9 – 16.5 (Y) (M) USA: 15.1, 14 – 18.6 (M) |
1909 (Y) (M) 961 (M) |
| 4 | 2006 | AUS: 15.2, 14.1 – 16.5 (Y) | 927 (Y) |
| 5 | 2007 | AUS: 16, 15 – 17.4 (Y) | 927 (Y) |
| N/A | 2009 | AUS: 19 – 22 (M) (O) | Tracking and locating survey only |
| F1 (Follow-up 1) | 2010 | AUS: 21, 17.9 – 24.6 (Y) (M) (O) | 2872 (Y) (M) (O) |
| F2 (Follow-up 2) | 2012 | AUS: 23, 20 – 26.9 (Y) (M) (O) | 2871 (Y) (M) (O) |
| F3 (Follow-up 3) | 2014 | AUS: 25, 22 – 28.9 (Y) (M) (O) USA: 25, 24 – 26 (M) |
2870 (Y) (M) (O) 955 (M) |
Key references
McMorris, B.J., Hemphill, S.A., Toumbourou, J.W., Catalano, R.F. and Patton, G.C. (2007). Prevalence of substance use and delinquent behavior in adolescents from Victoria, Australia and Washington State, United States. Health Education and Behavior, 34: 634-650
Primary institution
Collaborating institutions
Major funding sources
Contact
Cohort Representative
Address
Centre for Adolescent Health,Level 2 East, The Royal Children’s Hospital,
Parkville, VIC 3052
Social Development Research Group School of Social Work,
University of Washington, Seattle