Clinical utility of the Impact of Event Scale: Psychometrics in the general population

The Impact of Event Scale (IES; Horowitz, Wilner, & Alvarez, 1979), Trauma Symptom Inventory (TSI; Briere, 1995), Los Angeles Symptom Checklist (LASC; Foy, Sipprelle, Rueger, & Carroll, 1984), and Traumatic Events Survey (TES; Elliott, 1992) were administered to a sample of 505 participants from the general population. In this application of the IES, participants reported on "an upsetting event," as opposed to a specific stressor. The IES was found to be reliable and to have concurrent validity with respect to the TSI and LASC. IES scores varied as a function of race, but this relationship disappeared once race differences in exposure to potentially traumatic events (PTEs) were taken into account. Although the IES was predictive of PTEs, the traumatic stress scales of the TSI had more predictive and incremental validity than the IES. The current data suggest that an "upsetting event" version of the IES may be useful as a brief screen for nonarousal-related posttraumatic stress, but that its potential limitations should be taken into account. Normative data on this version of the IES are presented.