Criminal offending among males and females between ages 15 and 30 in a population-based nationwide 1981 birth cohort: Results from the FinnCrime Study

•We studied police-registered crime in a Finnish 1981 birth cohort at ages 15 to 30.•60% of males and 25% of females were registered for (other than minor traffic) crime.•Prevalence of crime peaks in late adolescence, but only for males.•Offending frequency among offenders is relatively stable by age.•Different crime types overlap each other, and crime accumulates in a small group.

We describe the epidemiology of crime between ages 15 and 30 in a population-based sample. We received police register data for 5405 males and females, representing the children born in Finland in 1981. We classified crimes into drug, violent, property, traffic, drunk driving, and sexual crimes, excluding minor traffic offenses. Of males, 60% and of females, 25% were registered for offending. For males, prevalence peaked in late adolescence, while for females, there was no peak age. Offending frequency remained stable for male offenders but was lower among adolescent female offenders. All crime types overlapped each other. Crime accumulated: 1% committed 34% of male and 56% of female offenses. In conclusion, the adolescent peak in offending reflects peaking prevalence among males, not females, nor frequency of offending among offenders. The crime problem is focused on two key groups: late adolescent males and the few males and females in whom crime concentrates.