Psychometric properties of goal‐attainment scaling in the assessment of mann's time‐limited psychotherapy

Abstract

This study tested the reliability and validity of Goal-Attainment Scaling (GAS) in assessing outcome in Mann's Time-Limited Psychotherapy (TLP). Judges constructed GAS scales for 33 patients on five dimensions: severity of symptoms, self-esteem, same-sex friendships, romantic relationships, and work performance. Patients in the treatment group received 12 sessions of TLP, whereas controls were in a waiting list for the same period of time (12 weeks) before starting time-limited psychotherapy. Judges rated all patients on GAS before beginning therapy, at termination, and follow-up. Mean interrater reliability of scores between pairs of judges was r = .88. Convergent validity of the GAS was confirmed by moderate to high correlations with the Health-Sickness Rating Scale (r = .70, p < .001), the Target Complaints Scale (r = .50, p <.01), and the Brief Symptom Inventory (r = .38, p < .05). The findings are discussed and recommendations are made for the reliable and valid use of the GAS in psychotherapy outcome research.