Students were first asked to choose, from a list of all students enrolled in the school and eligible for participation, all students with whom they had spent “free time” in the past month. Free time was defined as at least 10 minutes in which “you could talk about whatever you wanted,” and explicitly did not include class time or organized activities. The number of choices was unrestricted. Students were shown a list of all students they had chosen and asked to indicate for each a) on how many days in the past month they had spent free time with that student, and b) whether the student was a “best friend.” In this paper, best friend nominations defined the networks.
