Psychometric Properties
Reliability: QPASS scales were found to have strong internal consistency reliability (alpha coefficients: .79-.95) in a sample of 386 adult mental health outpatients (see table below).
Validity: QPASS scores on depression, anxiety, anger, phobic avoidance, obsessive-compulsivity, and psychoticism were found to have high positive correlations (ranging from .63-.83) with scores on similar scales in a sample of 82 outpatients (see table below). Consistent with expectations, moderately high coefficients were found for the Suicide and Violence Risk Scales when they were correlated with scales that less directly measure suicide risk and violence risk. In support of QPASS’s ability to assess overall psychological distress, the Global Psychopathology Index was found to have an exceptionally high .90 correlation with the Global Severity Index of the SCL-90 in the sample of 386 outpatients, offering very strong support for the use of QPASS for assessing overall psychological distress in mental health outpatients, a good indicator for predicting length of treatment.