Posttraumatic Stress Disorder Checklist for DSM-5 - EFA.xls

The instrument used is PCL-5 which is a 20 item instrument that measures the PTSD symptomatology based on the diagnostic criteria outlined in the DSM-5. The answers were in a form of a 5-point Likert scale to rate each item from 0 (not at all) to 4 (extremely) to indicate the concern about that particular symptom over the past month. A score of 2 (moderately) or greater is considered as an endorsed symptom. The scoring procedures used yielded a dichotomous indicator of diagnostic rank (of probable PTSD).<br><br>Construct validity was examined through Exploratory Factor Analysis (EFA) with an oblique “Promax” rotation. Oblique rotation is suitable for the investigation of latent constructs for which one expects to extract correlated dimensions. We used the Promax with Kaiser Normalization since the correlation between the factors was above 0.6. We performed an EFA as we seek to identify the smallest number of interpretable factors that can adequately explain the correlations among a set of PCL-5 items. Kaiser-Meyer-Olkin (KMO) and Bartlett’s test of sphericity were used to test for the appropriateness of factor analysis. The KMO measure may vary between 0 and 1; high values of sphericity mean that the variables are correlated and the analysis is feasible.<br><br>This study was approved by the Institutional Review Board (IRB) committee of the SGHUMC Faculty of Medicine, University of Balamand, Lebanon, which is registered with the U.S Office of Human Research Protections (OHRP) in the Department of Health and Human Services.