“…Four of the nineteen studies in this synthesis used random assignment of students to treatment and comparison groups (Allinder, Dunse, Brunken, & Obermiller-Krolikowski, 2001;Conte & Humphreys, 1989;Homan, Klesius, & Hite, 1993;O'Shea, Sindelar, & O'Shea, 1987).…”