Psychometric validation of the Spanish SDM-20: an occupational health screening tool for assessing workplace mobbing

The aim of this study was to psychometrically validate the Spanish version of the Polish SDM-20 questionnaire (Skala Doświadczania Mobbingu) as a screening instrument for assessing workplace mobbing in occupational health settings.

A cross-sectional online survey was conducted among 753 Spanish employees (65.5% women, age: 18-66 years). The factorial structure of the SDM-20 was examined using confirmatory factor analysis (CFA). Internal reliability was assessed using Cronbach's α and McDonald's ω coefficients. Convergent and divergent validity were evaluated through correlations with workplace bullying (Negative Acts Questionnaire - Revised - NAQ-R), burnout (Maslach Burnout Inventory - General Survey - MBI-GS9), and organizational climate measures.

Confirmatory factor analysis supported the original 3-factor model, encompassing person-related mobbing, work-related mobbing, and health-related harm, and demonstrated satisfactory model fit. All subscales showed high internal reliability. Strong positive correlations with workplace bullying and burnout measures supported convergent validity, whereas negative associations with organizational climate indicators provided evidence of divergent validity. The results confirm the structural stability and construct validity of the Spanish SDM-20.

The Spanish version of the SDM-20 is a reliable and valid instrument for screening workplace mobbing in occupational health contexts. By integrating behavioral exposure with a psychometrically assessed harm component, the instrument enables differentiation between exposure and clinically relevant victimization. Its brevity and robust psychometric properties support its application in occupational health surveillance and early risk detection. Int J Occup Med Environ Health. 2026;39(3):296-312.