The test was developed using a sample of responses from the comparison of 504 sets of results from a trial by students, taken from a larger sample of 950 first year university student responses. The scores were subsequently checked for validity against outpatient groups including patients suffering from anxiety, depression and other mental disorders. While the test was developed with individuals older than 17 year of age, due to the simplicity of language, there has been no compelling evidence against the use of the scales for comparison against children as young as 12.
The DASS-21 has been extensively normed, with data used for interpretive purposes based on a sample of 1794 non-clinical adults (Henrey & Crawford, 2005). Consistent with the DASS-42, the DASS-21 has internal consistency and concurrent validity in acceptable to excellent ranges (Antony et al., 1998).
The DASS is based on a dimensional rather than a categorical conception of psychological disorder. For full interpretive information please purchase the DASS manual at http://www2.psy.unsw.edu.au/groups/dass/order.htm
A raw score for the three subscales and the total raw score are given as output. For each of the three subscales percentiles, based on a community sample (n = 1794) are computed. In addition, scores for each subscale are categorised into five severity ranges: normal, mild, moderate, severe and extremely severe. The severity labels are used to describe the full range of scores in the population, so ‘mild’ for example means that the person is above the
population mean but probably still below the typical severity of someone seeking help (i.e. it does not mean a mild level of disorder).
Lovibond, S.H.; Lovibond, P.F. (1995). Manual for the Depression Anxiety Stress Scales (2nd ed.). Sydney: Psychology Foundation (Available from The Psychology Foundation, Room 1005 Mathews Building, University of New South Wales, NSW 2052, Australia