Equivalence of the short form of the reynolds adolescent depression scale across groups.

The present study examines the equivalence of the short-form version of the Reynolds Adolescent Depression Scale (RADS-SF) for measuring depression in adolescents across gender, age, and ethnic groups. A sample of 8,692 randomly selected New Zealand secondary school students participated in the Youth'07 Health and Wellbeing Survey that included the RADS-SF. The reliability was assessed using Cronbach's alpha and item-total correlations. The validity was assessed using multigroup confirmatory factor analysis, and correlation to other questions in the survey considered likely to be associated with depression. The RADS-SF scores ranged from 10 to 40 (Mdn = 18), with a mean score of 19.14 (SD = 6.19) and Cronbach's alpha of .88. Configural, metric, and scalar equivalence was supported across gender, age, and ethnic groups (New Zealand European, Māori, Pacific, Asian, and Other), with all tested models having good fit to the data. The correlations between the RADS-SF and other variables such as suicidal ideation and well-being were also equivalent across groups. The RADS-SF was found to be equivalent in measuring depression across age, ethnic groups, and gender in a large population of New Zealand adolescents.