Evaluation of the Posttraumatic Stress Disorder Checklist for DSM-5 Across United States and India Samples: An Item Response Theory Analysis Using the Graded Response Model

Objectives: The Posttraumatic Stress Disorder (PTSD) Checklist for DSM-5 (PCL-5) is frequently used to assess PTSD symptoms. Extending its psychometric investigations across distinct samples (United States and India), the aims of the present study included investigating the item characteristics, person fit, and differential item functioning (DIF) across the two samples. Method: We (a) conducted item analysis using the graded response model to examine item characteristics (thresholds and discrimination parameters) and (b) examined person fit to determine participants' response patterns. The U.S. sample included 176 trauma-exposed individuals seeking mental health treatment, and the Indian sample included 148 trauma-exposed ex-military personnel. Results: Results indicated low discrimination for Item 8 and low but acceptable discrimination for Item 17 for the U.S. and Indian samples, respectively. Across both samples, the most unused response categories were the middle-point or extreme (higher severity) categories (all response categories were better utilized in the Indian sample), and half the participants exhibited person misfit. Supplemental DIF analysis indicated that five items exhibited DIF indicating potential item bias; however, effect sizes for DIF were negligible. Conclusions: Although the PCL-5 demonstrated strong psychometric properties and showed promise for use across the samples differing on cultural and demographic characteristics, some of the items and the number of categories used to measure them could be revisited to create a more efficient instrument. Clinical Impact Statement Clinicians and researchers can use the Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) to compare posttraumatic stress disorder symptom severity across the examined samples from the United States and India. Further, the PCL-5 showed desirable item characteristics in both Indian and U.S. samples barring a few items. Last, clinicians and researchers could consider reducing the number of response categories as well as higher-severity response categories (especially for arousal items) when using the PCL-5 in the U.S. sample; such modifications do not apply for the Indian sample.