Scale Overview
The Impact of Event Scale – Revised (IES-R) was developed by Daniel S. Weiss & Charles R. Marmar (1997). It is designed to measure Post-traumatic stress disorder (PTSD) symptoms. The scale is intended for use with Adults.
Scale Structure
This instrument consists of 22 items organized into 3 factors/subscales: Intrusion, Avoidance, Hyperarousal.
| Factor / Subscale |
Items |
N |
| Intrusion |
1,3,6,9,14,16,19,20 |
8 |
| Avoidance |
5,7,8,11,12,13,17,22 |
8 |
| Hyperarousal |
2,4,10,15,18,21 |
6 |
Response Format
Respondents rate each item using a custom response format.
Response anchors: 0 = Not at all, 1 = A little bit, 2 = Moderately, 3 = Quite a bit, 4 = Extremely.
Scoring
Items are scored by subscale, with each subscale sum representing a distinct dimension.
Total scores range from 0 to 88. Interpretation guidelines:
- Normal / Subclinical: 0 – 23
- Mild PTSD Symptoms / Clinical Concern: 24 – 32
- Moderate to Severe PTSD Symptoms: 33 – 88
Psychometric Properties
Internal Consistency: The scale has demonstrated good to excellent internal consistency with reported Cronbach’s alpha values of High internal consistency for subscales.
Administration
The scale is self-administered and typically takes approximately 5 minutes to complete. It can be administered individually or in group settings. No special training is required for administration.