Objective: To examine aspects of the reliability and validity of the Reynolds Adolescent Depression Scale (RADS) in measuring depression in New Zealand adolescents of all major ethnic groups.
Method: A sample of 9699 randomly selected New Zealand secondary school students participated in the Youth2000 Health and Wellbeing Survey which included the RADS. Data from this survey have been used to assess some aspects of the reliability and validity of the RADS in the New Zealand context across different ethnic groups. Cronbach's alpha, item-total score correlations, correlation to other questions and a factor analysis were done in order to examine the internal reliability, content validity, convergent validity and construct validity of the data and compare to the original Reynolds validation study.
Results: Tests of the scale resulted in scores over 0.90 on Cronbach's alpha and high item-total score correlations, with a median correlation of 0.62 and 25 of the 30 correlations measuring more than 0.5. The scores were found to have similar factor structure to the original scale and the correlations to other depression related questions indicate acceptable concurrent validity.
Conclusions: On all of the tests conducted, the RADS was found to have acceptable reliability and validity for New Zealand adolescents across the major different ethnic groups, indicating that it is a valid and appropriate instrument to use with New Zealand adolescents.