Description

The Impact of an Event Scale (IES) is an assessment tool used to measure the effect of a painful or traumatic event on an individual. The IES was designed to evaluate the intensity of symptoms related to stress following a traumatic event, such as a natural disaster, accident, or other major loss.

Analysis

The Impact of an Event Scale assesses two main dimensions:

Intrusion:
It examines how frequently and intensely the individual re-experiences the events through distressing thoughts, images, or nightmares. It includes questions related to the frequency of flashbacks to traumatic memories.
Avoidance:
It measures the individual’s tendency to avoid thoughts, emotions, or situations associated with the traumatic event. It assesses how often the person avoids emotional responses or situations that cause discomfort.
The IES consists of questions answered on a Likert scale, usually ranging from 0 (not at all) to 5 (very much).

Purpose

The purpose of the Impact of an Event Scale is:

Symptom Assessment:
To provide a measurement of the intensity of post-traumatic stress symptoms or stress reactions associated with traumatic events.
Diagnostic Support:
To assist in diagnosing trauma-related disorders such as post-traumatic stress disorder (PTSD).
Progress Monitoring:
To monitor the progress of individuals undergoing treatment for post-traumatic stress and to adjust intervention strategies accordingly.

Scoring

Scoring of the Impact of an Event Scale includes:

Total Score:
Calculated based on the cumulative score of the individual items. Higher scores indicate greater symptom severity.
Subscale Separation:
The total score can be divided into two main subcategories: intrusion and avoidance, to better understand the different aspects of the impact of the traumatic event.

References

Horowitz, M. J., Wilner, N., & Alvarez, W. (1979). Impact of Event Scale: A Measure of Subjective Stress. Psychosomatic Medicine, 41(3), 209-218.
Weiss, D. S., & Marmar, C. R. (1997). The Impact of Event Scale – Revised. In Assessing Psychological Trauma and PTSD. Guilford Press.
Creamer, M., Bell, R., & Failla, S. (2003). Post-Traumatic Stress Disorder: The Impact of the Event Scale-Revised. Australian & New Zealand Journal of Psychiatry, 37(5), 554-562.