Abstract
The dimensionality of the Impact of Event Scale (IES) was analyzed using structural equation modeling (SEM). Responses from 321 individuals (62% response) who had experienced a mass murder of seven people 8 months earlier were obtained. A model with a general factor and three subordinate specific factors--Intrusiveness, Avoidance, and Sleep Disturbance--was developed. Scores on the original IES subscales and the SEM factors were related to scores on the General Health Questionnaire. It was concluded that the original subscales could, to a certain degree, be regarded as a reflection of negative affectivity. A more differentiated pattern emerged using the specific latent variables from the SEM analysis.