Factor analysis of the Impact of Events Scale with female bank staff following an armed raid

The aim of the present study was to explore the psychometric properties of the Impact of Events Scale [IES (Horowitz, Wilner & Alvarez, Pyschosomatic Medicine, 41, 209–218, 1979)] with 228 female bank staff who had been caught up in an armed bank raid. The IES was completed approx. 3 weeks after the incident and again at around 3 months by 147 of the women. Evidence is presented that the IES is composed of two major factors characterized as intrusion and avoidance which are associated with greater emotional distress. However, as with previous work, several discrepancies with the accepted scaling procedure are noted. Moreover, the factor structure appears to be different at 3 weeks compared to 3 months. Implications for the possible nature and course of symptomatology are discussed along with suggestions for further psychometric development.