Physical aggression, oppositionality and non-violent delinquency were measured using items from the Youth Self-Report questionnaire (Achenbach 1991). Scales comprised 3, 8, and 11 items respectively. Examples include “I physically attack people”, “I argue a lot”, and “I lie or cheat”. Response options were ‘not true’ (0), ‘somewhat true’ (1), or ‘very true’ (2), regarding behaviour during the last 6 months. Internal reliability was acceptable: Cronbach’s alpha was 0.65 for physical aggression; 0.76 for oppositionality; and 0.70 for delinquency.
