MST is a family- and community-based intervention that establishes close contact with families to understand and deal with the factors that cause the young person's antisocial behaviour. The intervention targets the individual's adjustment, family relationships, school functioning and peer group affiliations. Therapists help caretakers develop skills to intervene and operate changes in important domains such as young person's individual adjustment, their family relationships, school functioning, and peer group affiliations.

YOT intervention consisted of services currently available to young offenders in accordance with the Youth Justice Board National Standards.These services included supporting the young person to re-engage with education, with substance misuse problems and anger management; training them in social problem-solving skills; and programs to decrease vehicle-crime, violent-offending and knife crime. The treatments were delivered by professional social workers, specialist therapists or probation officers.

The number of records of offending behavior (count data) was obtained, and 6-month periods free of any offending behavior were also recorded (binary data). Records were obtained from the National Young Offender Information System (YOIS) database. YOIS records detail offence information, court appearances, criminal orders, police custody records, and arrest rates.

Antisocial behavior was assessed using the Self-Report of Youth Behavior (SRYB), a brief, valid measure of the prevalence and incidence in pre-adolescent and adolescent children of delinquent behavior such as vandalism, theft, burglary, and fraud; and the delinquency and aggression subscales of the Youth Self-Report (YSR) and the parent-completed Child Behavior Checklist (CBCL).