Dunedin rides again!

Choice, bro! By age 38, 20% of you will account for 97% of the crimes committed by your age cohort. And we can predict which of you are in that 20% by measuring 1) your parental income; 2) whether you were maltreated as a child; 3) your childhood IQ; and, 4) your self-control as a child.

Nature Human Behavior

Measuring childhood risk factors

We measured risk factors that are thought to augur poor adult outcomes. All risk factor measures have been described in previous reports about this cohort.

Childhood socioeconomic status⁴³ was defined as the average of the highest occupational status of either parent across study assessments from the cohort member’s birth through 11 years (1 = unskilled labourer; 6 = professional), on New Zealand’s occupational rating of the 1970s.

Childhood maltreatment⁴⁴ includes evidence of: (1) maternal rejection assessed at 3 years of age by observational ratings of mothers’ interaction with the study children, (2) harsh discipline assessed at ages 7 and 9 years by parental report of disciplinary behaviours, (3) two or more changes in the child’s primary caregiver, and (4) physical abuse and (5) sexual abuse reported by study members once they reached adulthood. For each child, our cumulative index counts the number of maltreatment indicators during the first decade of life; 63.7% of children experienced no maltreatment, 26.7% experienced one indicator of maltreatment (hereinafter ‘probable’ maltreatment), and 9.6% experienced two or more indicators of maltreatment (‘definite’ maltreatment).

Childhood intelligence⁹ was measured as IQ with the Wechsler Intelligence Scale for Children – Revised (WISC-R) administered at ages 7, 9 and 11 years. IQ scores for the three ages were averaged and standardized.

Childhood self-control⁹ during the first decade of life was measured using nine measures of self-control: observational ratings of children’s lack of control (ages 3 and 5 years) and parent, teacher and self-reports of hyperactivity, lack of persistence, inattention, impulsive aggression and impulsivity (ages 5, 7, 9 and 11 years). The nine measures were positively and significantly correlated. Based on principal components analysis, the standardized measures were averaged into a single composite comprising multiple ages and informants, with strong internal reliability α = 0.86.


Caspi, A. et al. Childhood forecasting of a small segment of the population with large economic burden. Nat. Hum. Behav. 1, 0005 (2016).