How Accurate is Qpass?
(Psychometric Properties)
As the table below shows, the three Negaffect (NA)
scales – Depression-Scan, Anxiety-Scan, and Anger-Scan) — were found to have
strong internal consistency reliability (alpha coefficients: .94-.95) in a sample of 386
adult mental health outpatients.
As the table also shows, scores on the NA Scales and the Clinical Scales
(assessing 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. 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. This finding
strongly supports the use of Qpass for assessing overall psychological distress in
mental health outpatients.
The Qpass Manual has over 20 pages of details on the psychometric properties of Qpass,
including its discriminative, factorial, and construct validity.
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