Rasch analysis supports the use of the Depression, Anxiety, and Stress Scales to measure mood in groups but not in individuals with chronic low back pain

This is the first study that used Rasch analysis to demonstrate that the DASS-21 subscales demonstrate adequate measurement properties for research involving groups with chronic pain. Only the DASS-21 depression subscale demonstrated adequate reliability for use with individuals with chronic pain. The use of a single DASS-21 aggregate score as a measure of “negative affect” was not supported.