“…However, compared with the university and adult population, there are fewer self-reports specifically designed for adolescents, both in the North America and Europe. That is why some studies have resorted to adaptations of instruments originally developed for adults, such as the versions of the Modified Rathus Assertiveness Schedule (MRAS; Del Greco, Breitbach, & McCarthy, 1981;Vaal & McCullagh, 1977), the Gambrill and Richey Assertiveness Inventory (AI; Goldberg & Botvin, 1993;Wills, Baker, & Botvin, 1989), or the Scale for Interpersonal Behavior (SIB; Bijstra, Bosma, & Jackson, 1994), and even self-reports designed for primary school pupils, confident/Competitive, Loneliness/Hostility, Friendship, Miscellaneous, and Cruelty/Social Anxiety, which accounted for 77% variance. However, given the great similarity between both factor structures, especially the first two factors, which accounted for the highest variance percentages, Spence and Liddle decided to accept the more parsimonious six-factor model originally proposed by Matson, Rotatori, and Helsel.…”