Abstract. This research developed a new scale to evaluate Self-Efficacy in Multiple Sclerosis (SEMS). The aim of this study was to investigate dimensionality, item functioning, measurement invariance, and concurrent validity of the SEMS scale. Data were collected from 203 multiple sclerosis (MS) patients (mean age, 39.5 years; 66% women; 95% having a relapsing remitting form of MS). Fifteen items of the SEMS scale were submitted to patients along with measures of psychological well-being, sense of coherence, depression, and coping strategies. Data underwent Rasch analysis and correlation analysis. Rasch analysis indicates the SEMS as a multidimensional construct characterized by two correlated dimensions: goal setting and symptom management, with satisfactory reliability coefficients. Overall, the 15 items reported acceptable fit statistics; the scale demonstrated measurement invariance (with respect to gender and disease duration) and good concurrent validity (positive correlations with psychological well-being, sense of coherence, and coping strategies and negative correlations with depression). Preliminary evidence suggests that SEMS is a psychometrically sound measure to evaluate perceived self-efficacy of MS patients with moderate disability, and it would be a valuable instrument for both research and clinical applications.
