Although the exact age of onset, peak, and age of desistance varies by offense, the general pattern has been remarkably consistent over time, in different countries, and for official and self-reported data.
For example, Farrington (1983, 1986a), in a longitudinal study of a sample of boys in London (the Cambridge Longitudinal Study), found an eightfold increase in the number of different boys convicted of delinquent behavior from age 10 to age 17, followed by a decrease to a quarter of the maximum level by age 24.
The study is continuing to follow these boys to see if their prevalence drops in early adulthood. (1998), using the Gluecks' data on 500 juvenile offenders from the 1940s, found that only 25 percent of them were still offending by age 32.
Much research has concentrated on the onset of delinquency, examining risk factors for onset, and differences between those who begin offending early (prior to adolescence) versus those who begin offending in midadolescence.
It has long been known that most adult criminals were involved in delinquent behavior as children and adolescents; most delinquent children and adolescents, however, do not grow up to be adult criminals (Robins, 1978).
Similarly, most serious, chronically delinquent children and adolescents experience a number of risk factors at various levels, but most children and adolescents with risk factors do not become serious, chronic delinquents.
A longitudinal study of a representative sample from high-risk neighborhoods in Denver also found a growth in the self-reported prevalence of serious violence from age 10 through late adolescence (Kelley et al., 1997).
Females in the Denver sample exhibited a peak in serious violence in midadolescence, but prevalence continued to increase through age 19 for the boys.
Many children reach adulthood without involvement in serious delinquent behavior, even in the face of multiple risks.
Although risk factors may help identify which children are most in need of preventive interventions, they cannot identify which particular children will become serious or chronic offenders.