A simple test at the age of three can predict if children will grow up to be a burden on society, New Zealand researchers say.

The tests on the brains of young children can reveal who is likely to become part of the minority of adults to use the biggest share of social services, new findings from the Dunedin Multidisciplinary Study show.

One thousand children born between 1972 and '73 were assessed on their language, motor skills and social behaviour. Low scores were a highly accurate indicator for who would end up in what they call "a high cost group".

The study found nearly 80 per cent of the group's adult economic debt from the health care, criminal justice and social welfare sectors was caused by 20 per cent of the study's 1000 participants.


University of Otago Dunedin Multidisciplinary Health and Development Research Unit director Professor Richie Poulton said the research, which analysed government databases and medical records of study members, was "pretty breathtaking".

"We [the unit] are pretty happy with this, and we have done a number of papers over the years but I would say this is one of the bigger ones."

The research found members of the Dunedin study who scored poorly in neurological evaluations and tests of verbal comprehension, language development, motor skills and social behaviour tests at 3 most often ended up taking the lion's share of social services as adults.

"We also found that members of this group tended to have grown up in more socio-economically deprived environments, experienced child maltreatment, scored poorly on childhood IQ tests and exhibited low childhood self-control," Poulton said.

While the "high cost" group made up only 22 per cent of study members, by mid-life they were responsible for 81 per cent of all convictions from the cohort, had received 66 per cent of the cohort's welfare benefits and accounted for 77 per cent of the years in which children of study members were growing up fatherless.

Many social service providers were already aware some people used more services than others, however it was the first time it had been shown "high-need/ high-cost" individuals could be recognised as children, he said.

The findings were enabled by a "unique situation" in which governmental data on benefits, criminal convictions and health services could be analysed alongside the smaller scale but more detailed information gathered by the Dunedin study.

He said the findings highlighted the importance of a social-sector wide approach to addressing childhood disadvantage early so costs for all members of society could be reduced.