The transition to adolescence involves significant changes for the family. To date, research on these changes and how they occur has been restricted by lack of suitable measures. An instrument—the Perspectives on Adolescent Decision-Making Questionnaire—was designed for such research. It examines 21 issues which can lead to conflict. The instrument was completed by 500 Italian adolescents aged 13 and 15. Sensitivity to age and sex differences was examined, and perceptions of personal choice, parental feelings, conflict and normal patterns for adolescents were analysed. The instrument offers promising possibilities for more effective study of parent/offspring relationships during the adolescent period.