The eight-item modified Medical Outcomes Study Social Support Survey: psychometric evaluation showed excellent performance

Abstract Objective Evaluation and validation of the psychometric properties of the eight-item modified Medical Outcomes Study Social Support Survey (mMOS-SS). Study Design and Setting Secondary analyses of data from three populations: Boston breast cancer study ( N = 660), Los Angeles breast cancer study ( N = 864), and Medical Outcomes Study ( N = 1,717). The psychometric evaluation of the eight-item mMOS-SS compared performance across populations and with the original 19-item Medical Outcomes Study Social Support Survey (MOS-SS). Internal reliability, factor structure, construct validity, and discriminant validity were evaluated using Cronbach's alpha, principal factor analysis (PFA), and confirmatory factor analysis (CFA), Spearman and Pearson correlation, t -test and Wilcoxon rank sum tests. Results mMOS-SS internal reliability was excellent in all three populations. PFA factor loadings were similar across populations; one factor >0.6, well-discriminated two factor (instrumental/emotional social support four items each) >0.5. CFA with a priori two-factor structure yielded consistently adequate model fit (root mean squared errors of approximation 0.054–0.074). mMOS-SS construct and discriminant validity were similar across populations and comparable to MOS-SS. Psychometric properties held when restricted to women aged ≥65 years. Conclusion The psychometric properties of the eight-item mMOS-SS were excellent and similar to those of the original 19-item instrument. Results support the use of briefer mMOS-SS instrument; better suited to multidimensional geriatric assessments and specifically in older women with breast cancer.