This questionnaire module contains questions on: academic self concept: anticipated self-perceived ability; achievement motivation in general; achievement motivation in school; anticipated intrinsic motivation; desired school-leaving qualification; domain-specific satisfaction (health, work/school, income/pocket money, leisure time, family life, partnership, friendships); existence of grandparents and frequency of meetings; expected probability to attain a degree; freetime and cultural activities with family members (parental report); freetime and cultural activities with family members (self-report); housing characteristics; long/short version of deviant-delinquent behaviour measure; occurence of externalising problem behavior (e.g. being restless and easily distracted, having tantrums, lying and cheating); occurence of internalising problem behavior (e.g. headaches and nausea, nervousness, and being easily scared); parenting style of mother, father, partner of father, partner of mother (child report); parenting style of mother, father, partner of father, partner of mother (parental self-report); patience; perceived self-efficacy; personality measures (BIG5); quality of familial environment (existence of bedtime routine, general atmosphere at home); risk aversion; satisfaction with sibling relationship; self esteem; twin relationship: warmth, conflict, affection, hostility, rivalry; twin-specific questions for siblings (e.g. relationship of the twins); twin-specific questions for twins themselves (e.g. relationship to other twin).