DASS-21 validity and reliability: what the research shows and what it does not
In a UK general-population sample of 1,794 adults, the DASS-21 scales were reliable, and the three scales were valid measures of depression, anxiety, and stress, although each also taps a general dimension of psychological distress. [6] That supports its use as a description. It does not support using labels as diagnoses. [3]
Where did the DASS-21 come from?
It is a short form of the 42-item DASS developed by Lovibond and Lovibond (1995). [6] Their site describes the DASS as three related self-report scales measuring depression, anxiety, and stress. [2]
How reliable are the scales?
Henry and Crawford reported Cronbach's alpha, a measure of internal consistency, of .88 for depression, .82 for anxiety, .90 for stress, and .93 for the total scale in their sample. [6]
Do the three scales measure three separate things?
The three scales are only partly separate. The best-fitting model in that study had a general factor of psychological distress plus specific factors for depression, anxiety, and stress. It fitted better than a model in which the stress scale simply measured negative affect. [6]
The authors concluded that the subscales can validly be used to measure the three dimensions, while each also taps a more general distress. [6] In plain terms, the scores overlap, and a high score on one is often accompanied by others.
What does the evidence not establish?
That the labels are diagnostic, that a score predicts what will happen to you, or that an online version behaves like the research one. The developers state it is not a diagnostic instrument. [3] The normative sample was a UK general adult population, and the authors provided normative data for it. [6] Findings in other countries, languages, or occupational groups may differ.
What should I check before trusting an online DASS score?
Check these things before you trust an online DASS score:
- Does it say it is the DASS-21 and cite the developers?
- Does it double the scale totals before using the severity table?
- Does it explain that the labels describe the population range and are not diagnoses?
- Does it say what to do next, including when to see a doctor?
- Does it say how it treats your data?
Sources and further reading
These links open external research and health-information websites.
- LuriaLab: DASS-21 test page
Twenty-one items, seven per subscale, past week, 0 to 3 scale, scoring statement, age 17+, and disclaimers. Read on 24 October 2026. - UNSW Psychology Foundation: Overview of the DASS
What the three scales cover, the 4-point rating, the past-week time frame, and the dimensional model. Read on 24 October 2026. - UNSW Psychology Foundation: DASS frequently asked questions
DASS-21 versus the full DASS, multiplying by 2, what the severity labels mean, that the DASS is not diagnostic, occupational stress, and age. Read on 24 October 2026. - DASS-21 response form (P. F. Lovibond, UNSW)
The 21 statements, the 0 to 3 labels, and the past-week instruction. - University of Bristol: DASS-21 scoring and interpretation
The sum-and-double instruction, the severity table, and the statement that the DASS is not a clinical instrument and cannot diagnose. - Henry and Crawford (2005): The short-form version of the Depression Anxiety Stress Scales (DASS-21): construct validity and normative data in a large non-clinical sample. British Journal of Clinical Psychology, 44, 227-239
A UK general-population sample of 1,794 adults. Full text read.
This page is educational. A questionnaire score cannot establish a diagnosis or explain the cause of your symptoms. If you are struggling, speak with a doctor or mental health professional, whatever your score. Read when to get help for work stress or find a helpline in your country.