The research sample was drawn from two sources; all adolescents in elementary schools in grades 8 to 10, a total of 11.430. The second sample consisted of adolescents from Stuðlar in the same age groups, a total of 39 individuals.
Úrtakið voru allir unglingar í grunnskólunum í áttundu til tíundu bekkjum sem voru 11.430 talsins og allir unglingar sem voru á Stuðlum í sömu aldurshópum sem voru 39 talsins.