The Psychometric Properties of an Internet-Administered Version of the Depression Anxiety and Stress Scales (DASS) in a Sample of Dutch Adults

• Published in: Journal of psychopathology and behavioral assessment 2018-06, Vol.40 (2), p.318-333
• Main Authors: Wardenaar, Klaas J., Wanders, Rob B. K., Jeronimus, Bertus F., de Jonge, Peter
• Format: Article
• Language: English
• Subjects: Anxiety; Behavioral Science and Psychology; Clinical Psychology; Discrimination; Internet; Item response theory; Mental depression; Personality and Social Psychology; Psychology; Quantitative psychology; Severity; Stress; Translation; Validity
• ISSN: 0882-2689; 1573-3505
• DOI: 10.1007/s10862-017-9626-6

Psychometric work on the widely used Depression Anxiety and Stress Scales (DASS) has mostly used classical psychometrics and ignored common internet-administered versions. Therefore, the present study used not only classical, but also modern psychometrics based on item response theory (IRT) to evaluate an internet-administered version of the DASS (Dutch translation). Internet-administered DASS data were collected as part of a large internet-based study in the Dutch adult population ( n  = 7972). Initially, external correlates (i.e. demographics other measures) and some classical psychometrics (internal consistency, convergent/divergent validity) of the DASS scales were evaluated. Next, IRT was used to investigate the scales’ dimensionality, discrimination and item-functioning. Finally, the DASS depression scale was further investigated by linking it to the more clinically-oriented Quick Inventory of Depressive Symptomatology (QIDS) using item response theory (IRT). Initial classical psychometric analyses supported the scales’ internal consistency (alpha = 0.94–0.98) and convergent/divergent validity. IRT analyses showed that each of the DASS scales was only suitable to measure variations in a very narrow and rather mild severity range. Linking the DASS depression scale with the QIDS also showed that the DASS depression scale discriminated best in the mild-moderate severity range, but not at higher severity levels that were covered by the QIDS. In conclusion, the scales of the internet-administered DASS show good internal consistency and validity. However, users should be aware that the scales discriminate best at mild-moderate severity ranges in the general population.