Background: Worldwide, children are becoming rare.  Nations increasingly view young people as a valuable resource for the economic and social wellbeing of whole societies. There is intense interest in early-years interventions to help all children achieve their potential. However, the return on investment from early-years intervention depends on how strongly early-years risk factors are linked to later costly adult outcomes. Much research has shown that childhood risk ‘X’ can predict poor adult outcome ‘Y’, but effect sizes have been modest. If childhood does not predict adult outcomes strongly then even the most effective interventions will bring only modest societal benefits. 

Method: We used data from the Dunedin Study, a four-decade longitudinal study of a birth cohort of 1000 New Zealanders. We examined risk factors in childhood and measures of social, health, and economic costs in adulthood, using a population segmentation approach.  

Results: Adult social and economic outcomes fit the Pareto principle: 20% of the cohort accounted for approximately 80% of the cohort’s months of social welfare benefits, years of absent-father childrearing, pack-years of cigarette smoking, pounds of overweight, hospital admissions, pharmacy prescription fills, criminal court convictions, and injury-related insurance claims. Moreover, an ultra-high-cost sub-segment of about 15% of the birth cohort was identified who accounted for the vast bulk of multiple social and economic problems. Risk factors measured in childhood that characterized this ultra-high-cost group were: low family socio-economic status, child maltreatment, low self-control, and low IQ.  Effect sizes were very large.  Predictive analyses showed that together, SES, maltreatment, self-control, and IQ measured in the first decade of life were able to predict 80% of the individuals who use most of multiple costly public services. We developed an index of the integrity of a child’s brain at age three years. This age-3 brain-integrity index was a strong predictor of the cohort members who four decades later became members of the ultra-high-cost population segment.

Implications: The vast bulk of a nation’s social services, crime control, and health-care are expended on a relatively small population segment. This segment of the population starts the race of life behind the rest of us, out of the starting blocks, and carries a brain-health handicap. Early-years interventions that reduce key childhood risk factors may bring surprisingly good return on investment.

Reception to follow in 4125 Sennott Square