At the age 15 assessment, adolescents' were also asked to nominate their “closest friend” of the same gender to be included in the study. Close friends were defined as, “people you know well, spend time with and who you talk to about things that happen in your life.” For adolescents who had difficulty naming a closest friend, it was explained that naming their “closest” friends did not mean that they were necessarily very close to this friends, just that they were close to this friend relative to other acquaintances they might have. In all cases, adolescents were able to name at least one closest friend using these criteria. Close friends reported that they had known the adolescents for an average of 5.0 years (SD = 3.2) at the age 15 assessment.
