October 20, 2016 2:00pm by David Farrar

A regrettable decision

New Zealand’s biggest longitudinal research project has been slashed in size by the Government, less than a year after the continuation of its contract was signed.

The Growing up in New Zealand Study is a 21-year project lead by Auckland University, following 7000 families from within 12 weeks before a child’s birth to their 21st birthday.

The study provides information about what shapes a child’s early development and how interventions might be targeted early, to give every New Zealand child the best start in life.

The continuation of its contract was agreed by government agency SuperU (formerly the Families Commission) in February this year.

Associate Social Development Minister Jo Goodhew confirmed the contract was reopened for negotiation under heavy questions in the House, last month. But she refused to give reasons why.

The Government has already poured tens of millions of taxpayer funds into the study since it began in 2008; it’s understood to have cost about $35-40m in development, and about $5m per year to run.

The study was allocated $15m by the Government in the May Budget. There are now fears that its downsizing will render previously collected data and the millions invested into it, meaningless.

Opposition MPs and a recent visiting academic brought to New Zealand by Superu itself, have decried moves to significantly alter the size of the group being studied.

A spokesman for Goodhew confirmed the contract had been signed, and the cohort of subjects reduced.

It’s been cut by more than two thirds – only following the lives of 2000 children.

Labour’s children’s spokeswoman Jacinda Ardern said it was a “shortsighted move”.

“We know how valuable past research like this has been. The size of this study though, meant we would have so much more information about ethnic groups growing up in New Zealand.

“That’s information we’ve never had before,” she said.

“You can’t just slice a study like this by two thirds and keep all of the value in that research.”

Superu, last week, flew a British academic to New Zealand to advise specifically on the use of evidence to improve social policy outcomes.

Chief executive of the Campbell Collaboration Howard White said it sounded “like a seriously bad idea”.

“The value of longitudinal studies – and having the same uniform observation, the same children, the same households – is enormous.

“The additional power it gives you and the sort of analysis you can do, in terms of charting trends, analysing social programmes they may have been exposed to – it’s just fantastic.

“And so the idea that you would somehow diminish the cohort, when you’ve got it already for 10 years now, seems to be unwise.”

He said it would “undermine the value” of the Government’s investment.

Goodhew said the reduction was to “future-proof” the study, and allow it to become “more sustainable”. But it’s future was not guaranteed.

“The Government has agreed to fund University of Auckland to undertake the eight year data collection wave of the Growing Up in New Zealand study with a sample of about 2000 children, larger than similar highly internationally regarded New Zealand studies. This confirms funding through to 2018/19.

This seems a regrettable decision to me. Once a longitudinal study has started, the value is in maintaining it. It is very different to a series of one off studies.

2,000 is a good sample size for top line data but if you want robust data for smaller demographics (area, ethnicity, income) the margin of error does get quite large.

If the study had started off at 2,000 then I’d have no problems with that as a size. But having already had two waves of 7,000 it will be a lot of value lost by downsizing it.