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 cultures and schools 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 adulthood.




Year 2002 2003 2004 2006 2007 2008 2010 2012 2014
Wave W1 W2 W3 W4 W5 W6 F1 F2 F3
Year level (cohort) Yr5 (Y)
Yr7 (M)
Yr9 (O)
Yr6 (Y)
Yr8 (M)
Yr10 (O)
Yr7 (Y)
Yr9 (M)
Yr9 (Y)

Yr10 (Y)

Yr11 (Y)

(Y)
(M)
(O)
(Y)
(M)
(O)
(Y)
(M)
(O)
Age range 9.8 – 16.5 yrs 11 – 17.4 yrs 11.9 – 16.5 yrs 14.1 – 16.5 yrs 15 – 17.4 yrs 16.1 – 18.6 yrs 17.9 – 24.6 yrs 20 – 26.9 yrs 22 – 28.9 yrs
# 2884 2884 1909 927 927 926 2872 2871 2870
Identifiers and miscellaneous
Anthropometrics
Behavioural problems
Demographics
Driving history
Education
General health
Mental health
Parenting
Physical activity and lifestyle
Puberty
Relationships
Reproductive health
Resilience and wellbeing
Respiratory health
Substance use
Temperament and personality
Uni/College policies
Workplace policies
Young adult transitions
Year 2002 2003 2004 2006 2007 2008 2010 2012 2014
Wave W1 W2 W3 W4 W5 W6 F1 F2 F3
Year level (cohort) Yr5 (Y)
Yr7 (M)
Yr9 (O)
Yr6 (Y)
Yr8 (M)
Yr10 (O)

Yr9 (M)
N/A N/A N/A N/A N/A
(M)
Age range 9.7 – 17.2 yrs 10.8 – 18.4 yrs 14 – 18.6 yrs N/A N/A N/A N/A N/A 24 – 26 yrs
# 2885 2885 961 N/A N/A N/A N/A N/A 955
Identifiers and miscellaneous Identifiers and miscellaneous
Anthropometrics
Behavioural problems Behavioural problems
Demographics Demographics
Driving history
Education Education
General health
Mental health Mental health
Parenting Parenting
Puberty
Relationships Relationships
Reproductive health Reproductive health
Resilience and wellbeing Resilience and wellbeing
Respiratory health Respiratory health
Substance use Substance use
Temperament and personality Temperament and personality
Uni/College policies
Workplace policies
Young adult transitions
Study Summary
Study name International Youth Development Study
Study abbreviation IYDS
Current principal investigator/s John Toumbourou (Deakin University)
Richard Catalano (USA)
Sheryl Hemphill (Australian Catholic University)
Current project manager Rachel Smith
Primary institution Centre for Adolescent Health, Murdoch Childrens Research Institute
Collaborating institution/s Social Development Research Group, University of Washington
Australian Catholic University
Deakin University
Major funding sources NHMRC
ARC
NIAAA
Study website http://www.rch.org.au/iyds/
Key reference for study (published study protocol) 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
Are data available to others outside study team? 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.
Study focus (e.g. social development) 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 (Y), 7 (M) or 9 (O)) were chosen at random; in a few cases, 2 classes from different year levels were randomly chosen at a school.
Study type (e.g. randomised control trial, cohort, case-control) Longitudinal cohort study
Year commenced 2002
Ongoing recruitment? No
Commencement sample (N) AUS: 2884
USA: 2885
(Total 5,769)
Annual attrition rate (%) Of the total eligible sample, 98.65% were re-surveyed in Wave 2 (2003),
97.59% in Wave 3 (2004),
86.93% in Wave 4 (2006),
89.2% in Wave 5 (2007), and
85.3% in Wave 6 (2008).
For the young adult follow up surveys, 84% of the total eligible sample were surveyed in follow up 1 (2010),
83% in follow up 2 (2012), and
87% in follow up 3 (2014).
Intergenerational (e.g. offspring)? No
Imaging (e.g. fMRI, ultrasound, retinal photograph)? No
Linkage (e.g. BioGrid, VPDC, NAPLAN, Medicare)? No
Biosamples (e.g. buccal, blood, hair)? No
Ethics approvals or requirements (e.g. specific, extended, unspecified, other)? The IYDS has ethics approval through the University of Melbourne Human Research Ethics Committee (060045X).
This project only (Specific consent)
Wave Year Age (mean, range) Eligible sample (not deceased, not withdrawn)
W1 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)
W2 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)
W3 2004 AUS: 14, 11.9 – 16.5 (Y) (M)
USA: 15.1, 14 – 18.6 (M)
1909 (Y) (M)
961 (M)
W4 2006 AUS: 15.2, 14.1 – 16.5 (Y) 927 (Y)
W5 2007 AUS: 16, 15 – 17.4 (Y) 927 (Y)
W6 2008 AUS: 17, 16.1 – 18.6 (Y) 926 (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)

IYDS Project Manager

Rachel Smith

Ph: 1 800 200 141
Email: rachel.smith@mcri.edu.au

Postal Address

Centre for Adolescent Health

Level 2 East
Royal Children’s Hospital
Parkville Victoria 3052
Email: iyds@rch.org.au