Juvenile detention, while often sharing the same characteristics as adult detention (solitary confinement, confiscation of personal possessions, wearing of a uniform), is not determined by the same criteria as adult detention. The majority of children in detention are held for conduct which would not be considered criminal in an adult, such as promiscuity, truancy, running away, incorrigibility and very minor offences. Children are denied trial by jury, individual access to a lawyer, and bail. Sentences may be indeterminate, which may mean that children serve longer than the adult maximum for a given crime, or may remain in detention when the crime was minor or nonexistent but there is no other institution to take them. In this way children without families often end up with longer sentences for minor crimes than those who have committed serious crimes (theft, assault, rape, murder) but whose families welcome them back. The effect of such confinement tends to make hardened criminals of people who might not have otherwise been so, especially since there are little or no rehabilitation facilities.
A school in Northern Ireland which runs custodial training schemes for persistent offenders aged 12 to 15, has a reconviction rate of 85 percent within two years of release. More than 90 percent of boys of 15 to 16 who have been to prison are reconvicted within four years of being released. The cost of keeping a child in one of the 295 places in local authority secure units in the UK is about £1,700 per week.