Social Support in Military Personnel: A Psychometric Examination of the Interpersonal Support Evaluation List-12

Introduction: Post Traumatic Stress Disorder (PTSD) occurs in 17% of the military population, which is substantially higher than the rest of the world (Hoge et al., 2004). Individuals with PTSD often experience a reduction in their quality of life and interpersonal relationships (Stansfeld, Fuhrer, Head, Ferrie, & Shipley, 1997). Much more work is needed to better understand how individuals in the military both with and without PTSD conceptualize social support. The goal of this project was to examine the factor structure of a commonly used measure of social support, the Interpersonal Support Evaluation List (ISEL-12-Cohen, Mermelstein, Kamarck, & Hoberman, 1985), which was purported to be comprised of three subscales: Appraisal, Belonging, and Tangible support (Cohen et al., 1985).

Method: A sample of 4,189 active duty service members from Fort Hood in Killeen, Texas were surveyed as a part of a larger study. Participants completed a variety of measures which included the ISEL-12, behavioral health outcome measures, physical health outcome measures, and psychological health outcome measures.

Results: An Exploratory Factor Analysis conducted on half the data showed that two factors— Accessible Social Support and Inaccessible Social Support (defined by positive and negative wording)-- should be extracted from the data. Confirmatory Factor Analyses conducted on the other half of the data shows that the hypothesized three factor correlated traits model did not fit the data very well, and that both the two factor model found in the EFA and a bifactor model with two specific factors did fit well, with the bifactor model fitting best. Measurement invariance across ethnicity and prior deployment status was observed, as were predicted relationships between social support and a variety of convergent and divergent factors.

Conclusion: According to the results of this study, the ISEL-12 should be scored at the total score level, and it can be used equally effective for different subgroups within this population. More work needs to be done to establish how the construct of social support is important to members of the military.