As landmark longitudinal study Growing Up in New Zealand reaches its 15th year, we reflect on its impacts so far, and the hopes for its future.

In 2009, a group of expectant mothers were approached by researchers at the University of Auckland to be part of a new study that would follow their and over 6000 other children’s lives. 

At the time, the team at Growing Up in New Zealand had big dreams of following these mothers and their kids over a 21-year span, influencing policy and perspectives on child health and wellbeing along the way. But back then, they may not have imagined the scale of impact the study has already achieved in its first 15 years.

“I want my child growing up feeling safe, confident and able to achieve what they set their minds to do – that they are not limited by our society,” said one of the expectant mums back in 2009. And in the years since, the study has helped to move Aotearoa towards a society where that dream is hopefully even easier to realise.

Growing Up in New Zealand (GUiNZ) is a longitudinal study aimed at helping improve understanding of how early life, including culture, education, wellbeing, interpersonal relationships and societal contexts impact people throughout their lives. What makes the study unique – and important – is its ability to paint a picture of the diverse socio-economic, cultural and ethnic makeup of New Zealanders, today and in the future.

Over its decade-and-a-half, the study’s phases have changed to fit the life changes that these tamariki are experiencing. From antenatal interviews with their mothers, to “starting school” questionnaires at age six and Covid-era wellbeing questionnaires in 2020, GUiNZ has provided New Zealand-specific data on thousands of topics relating to our young people and how they interact with the world.

Study director Sarah-Jane Paine (Tūhoe) says like many longitudinal studies, one of the biggest challenges they face is the upkeep of relationships with study participants, many of whom move regularly. “We know families are busy and have many competing priorities, so keeping in touch about what’s happening in the study and how their information is making a difference is really important.”

Adds Paine: “If we’ve got a strong and positive relationship, then I believe that flows into providing high quality, robust data, because then our participants understand why they’re involved, what they’re contributing, and why they’re important.”

Despite its participants not even being old enough to vote yet, their influence on policy in Aotearoa has been great. In 2023, the addition of folic acid to all non-organic bread making flour was made mandatory after GUiNZ showed that 9 out of 10 mothers were not getting the recommended amount of folate during pregnancy. 

In September 2021, the Healthy Eating Guidelines for New Zealand Infants and Toddlers was published, shaped in part by data gathered from GUiNZ participants, and in 2016, the government mandated fire alarm installation in all rental homes as a result of GUiNZ statistics that revealed more than one in four rentals didn’t have working smoke alarms.

Many of these changes seem obvious in hindsight, but having the scientific evidence to support policy interventions is vital, and one of the core functions of the study. “It’s quite hard to go back and imagine a time when smoke alarms weren’t mandatory as part of rental accommodation,” says Paine.

As proud as she is of the policy changes that have come from the study so far, she says the over 100 million data points they’ve collected are just as important – like one in five 12-year-olds had experienced material hardship at some point in their childhood and that their families were being forced to make choices to get by – 21% putting off dentist visits, 18% unable to afford contents insurance, and 8% not being able to pay their bills on time.

“While we’re not at the point of being able to say that piece of information has created policy change, it’s really important that we were able to bring that statistic through,” says Paine. “We know this, so what are we going to do?”

The kids themselves are now at an age where they can understand more clearly the impact their responses and data is having on the country. 

Asked at age eight why they like being a part of GUiNZ, one said they enjoy being able to “help New Zealand be a better place”. Another mentioned their pride in helping “to make sure that the next generation can live a happy and healthy life”.

While longitudinal studies are not new to New Zealand – you’ve probably heard of the Dunedin Study that began in the 1970s – GUiNZ is uniquely able to capture the impacts of technological and societal changes on participants’ lives, while taking a holistic view of how complex factors interact over time. “We’re proud of the study’s ability to offer insights into what it’s like to be a young person growing up in Aotearoa today, and to provide those designing policies or services for children and families with robust, relevant data to inform their work,” says Paine. 

Since the very beginning, Paine says, GUiNZ has had an idea of the topics it wanted to focus on, but when big, potentially life-altering events happen, the team’s strong relationships with the study cohort means they can quickly collect data while it is fresh. 

When New Zealand was hit by Cyclone Gabrielle in February of 2023, tamariki in some of the hardest hit areas were asked to fill out a questionnaire about its impacts on their lives. Almost 700 responses were recorded by participants and their whānau from Auckland, Northland, the East Coast and Hawke’s Bay, and results were presented in tailored reports for each region, highlighting the varied challenges and recovery processes needed. GUiNZ is to date the only study that captured the thoughts and feelings of young people about these extreme weather events in Aotearoa.

After the success of the questionnaire post-Cyclone Gabrielle, the study team has now started to think about the impacts of climate change on young people, including climate anxiety, which has been having a huge impact on young people internationally.

“If it’s important for young people now then it’s important for our study,” says Paine.

As the participants turn 15, they enter a new, complex stage of their life, and Paine says the next phase of the study will focus on topics relevant to this stage of life, including identity development.

“That sense of self, the growing or evolving sense of autonomy. That’s something that we can track, because we’ve been following the young people since before they were born… so we can see how that changes as they age,” she says.

In its quest to understand better how our young people are interacting with the world around them, GUiNZ has provided the basis not only for systemic change, but the evidence to help us all make decisions to create an Aotearoa that allows this flourishing.

At its initiation, those running the study had visions of continuing it until participants turned 21. While Paine can’t say for sure what its duration will end up being, she is already thinking about how childhood factors can impact members of Gen Z even later into their adulthood.

“The investment of the families to date has been huge. They’ve spent tens, hundreds, thousands of hours contributing information to the study because they believe that Aotearoa can be the best place in the world for their children and for their mokopuna,” says Paine.

It would be hard to look at the effects of the study and say it hadn’t achieved success already, and its data and insights are only set to become richer as time goes on. 

For Paine, success is about how the participants feel they’re contributing to a changing Aotearoa: “that the people, the whānau, the rangatahi in particular feel really proud of being involved in the study, and that pride grows because they can see we are living up to their hopes and aspirations.”