Objectives: To determine the Minimal Clinically Important Difference (MCID) and Robust Clinically Important Difference (RCID) of the Mayo-Portland Adaptability Inventory-4 (MPAI-4) as measures of response to intervention.
Methods: Retrospective analysis of existing data. Both distribution- and anchor-based methods were used to triangulate on the MCID and to identify a moderate, that is, more robust, level of change (RCID) for the MPAI-4. These were further evaluated with respect to clinical provider ratings.
Participants: Data for individuals with acquired brain injury in rehabilitation programs throughout the United States in the OutcomeInfo Database (n = 3087) with 2 MPAI-4 ratings.
Main measures: MPAI-4, Supervision Rating Scale, Clinician Rating of Global Clinical Improvement.
Results: Initial analyses suggested 5 T-score points (5T) as the MCID and 9T as the RCID. Eighty-one percent to 87% of clinical raters considered a 5T change and 99% considered a 9T change to indicate meaningful improvement.
Conclusions: 5T represents the MCID for the MPAI-4 and 9T, the RCID. Both values are notably less than the Reliable Change Index (RCI). While the RCI indicates change with a high level of statistical confidence, it may be insensitive to change that is considered meaningful by providers and participants as indicated by the MCID.