The Milestone Moment for New Zealand's Largest Child Development Study

As the cohort of the Growing Up in New Zealand (GUiNZ) longitudinal study reaches their late teens, a pivotal chapter unfolds. Over 6,000 young people, now aged around 17, are being invited to take ownership of their involvement in this groundbreaking research effort. Launched in 2008, GUiNZ has tracked these individuals from before birth, capturing more than 100 million data points across multiple waves. This latest phase, the 17-Year Data Collection, marks the first time participants provide their own consent, reflecting a shift toward autonomy as they navigate the complexities of adolescence.

Hosted by the University of Auckland, the study represents a cornerstone of New Zealand's research landscape. It offers unparalleled insights into child health, wellbeing, and development in a diverse, modern context. With recent government funding of $16.8 million extending the project through two additional waves, the initiative underscores its enduring value to policymakers, educators, and communities aiming to support the next generation.

Understanding the Growing Up in New Zealand Study: Origins and Scope

Growing Up in New Zealand began recruiting over 6,800 pregnant women and their partners between 2008 and 2009, resulting in a cohort of approximately 6,476 children born around late 2008 to early 2009. Designed as a contemporary longitudinal study, GUiNZ follows these individuals until at least age 21, documenting their physical, social, emotional, and cognitive trajectories. Unlike earlier studies focused on specific demographics, GUiNZ intentionally oversampled Māori, Pacific, and Asian families to mirror New Zealand's ethnic diversity, providing a nationally representative picture.

The study's methodology combines surveys, interviews, biological samples, and administrative data linkages, conducted at key life stages: prenatal, infancy (9 months), early childhood (2 years, 4.5 years), school entry (5-6 years), middle childhood (8 years), pre-teen (12 years), and now late teens (15 and 17 years). This comprehensive approach reveals how early experiences influence long-term outcomes, from health disparities to educational success.

Key to its success is participant retention, with rates consistently above 80% in recent waves, far exceeding many international cohorts. The University of Auckland's Centre for Longitudinal Research oversees operations, ensuring ethical standards and data security through robust privacy protocols.

Previous Waves: Building a Foundation of Insights

Over 17 years, GUiNZ has delivered transformative findings. Early waves highlighted vulnerabilities in the first 1,000 days, showing how prenatal stress and socioeconomic factors predict later health issues. At age 4.5, reports like "Now We Are Four" detailed preschool experiences, revealing 97% of children in early education but persistent inequalities in access and quality.

The 8-year wave introduced child self-reports, uncovering school transitions' impact. By age 12, data exposed diet inequities—high sugar and fat intake disproportionately affecting vulnerable groups—and the role of arts participation in wellbeing. The 2025 15-Year Check-In, a snapshot survey, delved into teen life amid COVID-19 and cyclones, emphasizing school satisfaction's link to mental health and the cost-of-living pressures on aspirations.

These insights have shaped policies on healthy lunches (Ka Ora, Ka Ako), mental health support, and cultural responsiveness, proving GUiNZ's real-world utility. For instance, evidence from the study influenced expanded free school meals to address adolescent nutrition gaps identified in diverse communities. Learn more about key findings from past waves.

The 17-Year Data Collection: What Teens Will Share

Running from May 1 to mid-October 2026, this wave shifts to a longitudinal format beyond snapshots, linking teen experiences back to infancy. Participants complete online questionnaires via the HOME portal, savable across sessions, covering home and school life, friendships, cultural connections, health, and wellbeing. Caregivers provide proxy data and their own updates if the young person consents.

Topics probe critical late-teen transitions: identity formation, future planning (careers, further study), independence, relationships (romantic, peer, family), and environmental influences like housing costs and climate events. Mental wellbeing assessments build on prior data to track resilience factors, while diversity-focused retention targets Māori (23%), Pacific (23%), and Asian (24%) youth ensure equitable representation.

Incentives include instant vouchers upon completion, with support hotlines and mental health resources available. This participant-centered design respects rangatahi agency while maximizing data richness for analysis.

Teen Consent: Empowering the Next Generation of Contributors

A landmark ethical evolution, the 17-year wave requires individual consent from those over 16, transitioning from parental proxy. Detailed information sheets outline data use, Stats NZ linkages, and withdrawal rights, empowering teens to shape their legacy. Research Director Professor Sarah-Jane Paine notes, "This is where young people take ownership... reflecting the value they place on contributing to a better Aotearoa."

This approach fosters trust, vital for retention in longitudinal research where dropout risks bias findings toward privileged groups. By prioritizing youth voice, GUiNZ models best practices in ethical cohort studies, influencing global standards at institutions like the University of Auckland.

University of Auckland's Pivotal Role in Leading GUiNZ

Headquartered at the University of Auckland, GUiNZ exemplifies NZ's higher education prowess in population health research. The Centre for Longitudinal Research, under Professor Paine, coordinates multidisciplinary teams spanning epidemiology, psychology, sociology, and Māori/Pacific health experts. Collaborations with Stats NZ, MSD, and Oranga Tamariki amplify impact.

UoA's infrastructure—advanced data labs, ethical oversight, and community engagement—ensures high-quality outputs. Faculty publications from GUiNZ data appear in top journals like The Lancet and Nature, elevating NZ research globally. Students gain hands-on experience, from PhD theses to internships, bridging academia and policy.Explore population health programs at University of Auckland.

Diversity and Representation: Reflecting Aotearoa's Rainbow

GUiNZ's cohort mirrors NZ's diversity: 52% European, 24% Māori, 23% Pacific, 24% Asian (overlaps), and 12% other. This intentional design counters underrepresentation in research, yielding nuanced insights like higher wellbeing resilience in Māori whānau through cultural connections.

The 17-year wave prioritizes retention among priority groups via tailored outreach—te reo Māori materials, Pacific navigators—ensuring findings address inequities. This commitment aligns with UoA's equity goals, informing targeted interventions like culturally safe mental health services.

Policy Impact and Broader Research Contributions

GUiNZ data drives change: influencing free school lunches, cyclone recovery supports, and teen mental health strategies. Recent 15-year findings linked school anti-bullying to lower depression rates, prompting curriculum reviews. The $16.8m extension (Sep 2024) enables waves at 17 and 21 years, tracking into adulthood.Government funding announcement details.

Beyond policy, open data access empowers researchers worldwide, fostering collaborations. UoA leverages GUiNZ for grants, publications (300+), and training, positioning NZ as a longitudinal research leader.

Challenges and Strategies for Sustained Participation

Maintaining engagement after 17 years demands innovation. Digital tools like the HOME portal simplify access, while incentives and personalized follow-ups boost response. Privacy assurances—de-identified data, secure storage—build trust amid rising data concerns.

Challenges include life transitions (moving, busy schedules) and fatigue, addressed via flexible timing and youth co-design. Success here ensures robust, unbiased data for decades.

Future Outlook: Shaping Adulthood Pathways

Linking 17-year data to prior waves illuminates how early adversities (e.g., poverty, trauma) interact with teen choices, predicting outcomes like employment, health, and family formation. Projections suggest insights into intergenerational effects, climate resilience, and digital wellbeing.

For NZ universities, GUiNZ cements UoA's research excellence, attracting talent and funding. As teens consent, they co-author evidence for a thriving Aotearoa, from equitable education to mental health reforms.

Participating in GUiNZ: A Call to Rangatahi

Teens receive invites via email/portal; consent and questionnaires take ~1-2 hours. Claim vouchers instantly, access support anytime. Your voice matters—contribute to policies supporting your peers. Contact: contact@growingup.co.nz or 0508 476 946.

Explore careers in longitudinal research at NZ universities via University jobs in New Zealand.

Photo by Dario Brönnimann on Unsplash