The CPSS has demonstrated good psychometric properties(Foa et al.2001), including in research with Latino schoolchildren (Kataoka et al.2003). In the current sample, theCPSS total (Time 1 and Time 2α=0.91), re-experiencing(Time 1 Englishα=0.85, Spanishα=0.81; Time 2 Englishα=0.83, Spanishα=0.83) avoidance (Time 1 Englishα=0.80,Spanishα=0.79; Time 2 Englishα=0.79, Spanishα=0.86),and arousal (Time 1 Englishα=0.73, Spanishα=0.72; Time 2Englishα=0.75, Spanishα=0.76) scales demonstrated goodinternal consistency.ProcedureA total of 331 students from 10 6thgrade and 2 mixed-gradehomeroom classrooms were recruited for participation.Research staff invited students to participate and distributed aletter and consent form for students to deliver to their caregiver.Students who returned a signed consent form, regardless ofwhether consent was provided on the form, received a smallincentive (e.g., a pencil or snack) and classrooms with at least95 % of students returning a consent form earned a classroomreward. A total of 273 (82.5 %) parents returned a signed formand of these, 170 (62.3 %) parents provided consent for theirchild to participate in the study. All students also providedassent to participate. This represents an overall recruitmentrate of 51.4 %. Because some students withdrew from theschool before data collection began, the overall sampleincluded 167 students at Time 1 and 161 students at the Time2 assessment 6 months later (96.41 % retention rate). Given thatexposure to trauma is a pre-requisite for posttraumatic stressdisorder, analyses in the current study focus on the 148 students(91.9 % of the overall sample) who reported at least someexposure to violence between the Time 1 and Time 2assessments.Study measures were administered to groups of students,with trained research staff reading all instructions and itemsaloud to the group and students providing individualresponses privately by marking their response on the surveyitself. Additional research staff were available to provideindividual assistance to students as needed. During the Time1 assessment, children completed measures of behavioralinhibition/activation and symptoms of PTSD and received a$10 merchandise gift card as an incentive. During the Time2 assessment, children provided reports of exposure to vio-lence since the Time 1 assessment and current symptoms ofPTSD. They received one $15 merchandise gift card forparticipation at Time 2.All study materials were available in English and Spanishand students had the option of deciding which language theywanted to complete measures in. Most participants elected tocomplete measures in English (82.4 %), while 17.6 % electedto complete measures in Spanish. Spanish versions of mate-rials without an existing translation were created through therecommended procedure of translation, back-translation, andsubsequent reconciliation of discrepancies (Marín and Marín1991). All study procedures were approved by theInstitutional Review Board at the University of California,Los Angeles.