Impact of Event Scale – Revised

What it measures

A widely used measure of subjective distress related to a specific traumatic event. The revised version adds a Hyperarousal subscale to the original IES (Horowitz et al., 1979). Although it preceded the DSM-IV PTSD diagnosis, it remains one of the most cited trauma measures and is frequently used alongside the PCL-5.

Response format

Likert (0–4, not at all to extremely) over the past 7 days; total 0–88

Representative items

• Any reminder brought back feelings about it. (Intrusion)
• I tried not to think about it. (Avoidance)
• I stayed away from reminders of it. (Avoidance)
• Other things kept making me think about it. (Intrusion)
• I was watchful and on guard. (Hyperarousal)

Usage notes & scoring

Freely available for research — widely reproduced in published papers. Administered with reference to a specific identified stressful event. Total score >=33 suggests probable PTSD. Three subscale scores provide a symptom profile. Predates DSM-5 but remains widely used for its brevity and sensitivity to change in RCTs. More recent measure is the PCL-5.

Recommended companion scales

Citation

Weiss, D.S., & Marmar, C.R. (1997). The Impact of Event Scale – Revised. In J.P. Wilson & T.M. Keane (Eds.), Assessing psychological trauma and PTSD (pp. 399–411). Guilford Press.

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