The Authenticity Scale as an Outcome Measure for Psychotherapy: A Psychometric Evaluation

We aimed to evaluate how the Authenticity Scale, a measure of authenticity based on humanistic psychology, functioned as an outcome measure for psychological therapies. Ninety participating clients completed the Authenticity Scale at set intervals throughout their therapy. We considered the measure's reliability, construct validity, acceptability, and sensitivity to therapeutic intervention. The Authenticity Scale and each of its subscales (Authentic Living, Accepting External Influences, and Self-Alienation) were found to have excellent internal reliability and very high completion rates. The full scale was also found to be sensitive to psychotherapeutic intervention, along with two of its three subscales. However, subscale intercorrelations revealed issues with the factor structure of the measure, with one subscale not correlating with the other two, drawing into question whether the Authenticity Scale should be seen to operationalize a single, multi-faceted construct as intended. Our study provides preliminary evidence that the Authenticity Scale can be used as an outcome measure in clinical practice, though caution and further psychometric testing are strongly recommended.