A psychometric examination of the Impact of Event Scale in a sample of child trauma victims

The Impact of Event Scale (Horowitz, Wilner, & Alvarez, 1979) is a 15-item self-report measure of trauma-associated stress symptoms that was developed for adult populations. Although the IES was developed for adults, it has been used with children and adolescents following various traumatic events. Little research has been conducted on the scale's use with children. Only two published studies exist that examined the psychometric properties of the scale with child and adolescent samples. Both used principle components analysis, and both yielded findings that were inconsistent with one another and with the original stress response formulation of Horowitz et al. (1979). In the current study, confirmatory factor analysis was employed to test these two models as well as a third model representing the findings of Horowitz et al. (1979) to determine which of these three models provided the best fit in a sample of child trauma victims. This sample included 47 boys and 77 girls ages 7-17. Results indicate that the model representing the two-dimensional structure of the original stress response formulation provided the best fit. This finding supports the continued use of the IES in this population.