Comparing the psychometric evidence of the Depression, Anxiety, and Stress Scale-21 (DASS-21) between Spanish and Chinese primary schoolteachers: insights from classical test theory and rasch analysis.

backgroundPrimary schoolteachers play a pivotal role in the education of children, highlighting the importance of addressing their psychological well-being and mental health. While the Depression, Anxiety, and Stress Scale-21 (DASS-21) is a globally recognized instrument for evaluating mental health, its systematic validation among primary schoolteachers, particularly in a cross-national context, remains understudied. The present cross-cultural study evaluated the psychometric properties of DASS-21 among primary schoolteachers in Spain and China to compare the DASS-21 between teachers across Western and Eastern cultures.

methodsThe study sample comprised 1,350 Spanish and 2,580 Chinese primary schoolteachers. The DASS-21, alongside the Emotional Exhaustion Scale for Teachers, was used to evaluate its psychometric properties. The construct and concurrent validity of the DASS-21 were examined using Rasch analysis, Confirmatory Factor Analysis (CFA), and Structural Equation Modeling (SEM). Additionally, measurement invariance was tested across two national teacher cohorts.

resultsRasch analysis confirmed the validity of most DASS-21 items among both the Spanish and Chinese teachers, with only the same item from the Anxiety subscale showing inadequate fit in both countries. CFA across both countries initially favored a bifactor model, which was subsequently excluded due to problematic factor loadings. Instead, a single-factor model provided the best fit for Chinese teachers, while a correlated three-factor model was optimal for Spanish teachers. SEM demonstrated the DASS-21's concurrent validity with emotional exhaustion, with consistent findings across both samples. After excluding Differential Item Functioning (DIF) items, strict measurement invariance between Spanish and Chinese teachers was achieved, as verified by multi-group CFA.

conclusionThe DASS-21 exhibits commendable psychometric properties, rendering it a suitable instrument for evaluating the mental illness of primary schoolteachers in both Spain and China.