TABLE 1

Sample Characteristics at T1 (N = 1132)

VariableValue
Age, y
 Mean ± SD13.95 ± 1.18
 Range11.49–17.89
Gender, no. (%)
 Male596 (52.7)
 Female536 (47.3)
Ethnic background, no. (%)a
 Dutch897 (79.2)
 Western124 (11.0)
 Non-Western111 (9.8)
Educational level, no. (%)
 Vocational education429 (40.3)
 College or university preparatory636 (59.7)
  • a Dutch = self and both parents born in the Netherlands; Western = self or a parent born in Europe, the United States, Canada, Australia, or New Zealand; non-Western = self or a parent born in an African, Middle Eastern, Asian, or South American country.