Measurement Properties, Longitudinal Measurement Invariance, and Short-Term Stability of the RCADS Major Depressive Disorder Subscale in Vietnamese Lower Secondary School Students

This study evaluated the suitability of the RCADS-MDD for assessing depressive symptoms among 805 Vietnamese lower secondary school students by examining its internal structure, reliability, measurement invariance, associations with related constructs, short-term temporal stability, and measurement error. Confirmatory factor analyses supported a one-factor structure at both assessment waves, with good internal consistency, although average variance extracted remained below the conventional threshold. Longitudinal configural, metric, and threshold invariance were supported, indicating that scores could be meaningfully compared across the two assessment occasions. Measurement invariance was also supported across gender, grade level, and school at both waves, supporting the comparability of scores across key student subgroups. Correlations with related psychological constructs provided additional evidence for the interpretability of RCADS-MDD scores. Scores demonstrated moderate rank-order stability over the short retest interval. However, indices of absolute agreement, standard error of measurement, minimal detectable change, and Bland-Altman analysis indicated that small changes in individual scores may reflect measurement variability rather than meaningful change. Overall, the findings support the RCADS-MDD as a suitable measure for assessing depressive symptom severity and for group-level comparisons among Vietnamese lower secondary school students, while caution is warranted when interpreting small score changes at the individual level.