Now We Are 12: Introduction to the Growing Up in New Zealand 12-Year Data Collection Wave

The aim of this document is to provide a summary of the 12-year Data Collection Wave (DCW) that occurred between September 2021 and October 2022, during which the Growing Up in New Zealand (GUiNZ) cohort of young people (mean age = 12.30 years, standard deviation = 0.27 years) completed their own questionnaires. This allowed for their voices to be heard directly, and for information to be gathered on their identity, health and wellbeing, relationships, perspectives, and priorities.

Growing Up in New Zealand is a longitudinal study that collects contemporary, population-relevant information to understand the development and wellbeing of children growing up in New Zealand in the 21st century. The study began by recruiting pregnant mothers who had expected delivery dates between 25 April 2009 and 25 March 2010 and were residing in the geographical areas defined by the three contiguous District Health Board regions (DHBs) of Auckland, Counties Manukau and Waikato. The cohort of 6,853 children recruited at baseline was diverse, broadly generalisable to the New Zealand birth population at the time, and of sufficient size to provide adequate statistical power for complex analyses of developmental trajectories within subgroups (including by ethnicity and area-level deprivation). Growing Up in New Zealand has since carried out multiple significant DCWs. This report provides background information on the 12-year data collection wave, descriptive statistics on the cohort at age 12 and retention rates since the start of the study.