Discriminative versus evaluative assessment: some observations on goal attainment scaling

Goal attainment scaling has been described in the rehabilitation literature as a method of evaluation designed to monitor client progress, structure team conferences, and provide information on overall program evaluation. The appropriate use of goal attainment scaling in clinical environments depends on a clear understanding of its strengths and weaknesses. The primary strength of goal attainment scaling is the ability to evaluate individualized longitudinal change. Goal attainment scaling is not a methodology designed to assess functional status. Confusion occurs when evaluation tools designed to discriminate between persons (determine status) are used to assess change in individual patients over time. This paper describes the strengths and weaknesses of goal attainment scaling as a methodology for evaluating clinical change. The process of evaluative assessment with goal attainment scaling is compared to discriminative assessment where the purpose is to distinguish between persons or to classify persons into predefined categories.