Goal attainment scaling in rehabilitation: a literature-based update.

Goal Attainment Scaling (GAS) is a method for quantifying progress on personal goals. Turner-Stokes's guide to GAS is a method for quantifying progress towards personal goals. Turner-Stokes's guide and the use of Kiresuk's T-score are the most widely used GAS-based approaches in rehabilitation. However, the literature describes a number of other approaches and emphasizes the need for caution when using the T-score. This article presents the literature debates on GAS, variations of GAS (in terms of the score level assigned to the patient's initial status and description of the scale's different levels), the precautions to be taken to produce valid GAS scales and the various ways of analyzing GAS results. Our objective is to (i) provide clinical teams with a critical view of GAS (the application of which is not limited to a single research group's practices) and (ii) present the most useful resources and guidelines on writing GAS scales. According to the literature, it appears to be preferable to set the patient's initial level to -2 (even when worsening is a possible outcome) and to describe all five GAS levels in detail. The use of medians and rank tests appears to be appropriate, given the ordinal nature of GAS.