Test–retest stability, convergent validity, and sensitivity to change for the Goal‐Based Outcome tool for adolescents: Analysis of data from a randomized controlled trial

OBJECTIVE(S): To examine the psychometric properties of the idiographic Goal‐Based Outcome (GBO) tool for young people: test–retest stability, convergent validity, and sensitivity to an intervention. METHODS: This measure validation study used data from a randomized controlled trial of school‐based humanistic counseling. We used multilevel analyses to assess test–retest stability, convergent validity of the GBO tool against nomothetic measures of mental wellbeing, and sensitivity to an intervention. RESULTS: The GBO tool showed acceptable stability over a 6–24 week period; moderate convergent validity with nomothetic measures of mental well‐being, self‐esteem, and depression; and greater sensitivity to an intervention than a measure of psychological distress. CONCLUSIONS: The GBO tool shows evidence of having acceptable psychometric properties and is suitable for monitoring change on individual goals. It may also have the capacity to function as a population‐level indicator of outcomes in conjunction with the use of other measures of mental health and wellbeing.