The Functional Status Index: reliability and validity of a self-report functional disability measure

Practical, reliable and valid functional assessment instruments are needed to assist health providers in planning a patient's discharge from hospital and determining the need for rehabilitation or longterm care. In addition, such instruments can be used in clinical and epidemiological research. Several methods of assessing functional performance are available. Patient self-report offers many advantages: cost, speed of obtaining assessments and the potential for assessing a wide range of complex functional dimensions. Criticisms of this approach center around the degree to which the data are a reliable and valid reflection of patient function. We developed a Functional Status Index (FSI) and assessed its validity in 47 patients with hip fracture by comparing it to the results of objective functional performance tests. Our results indicate that patient self-report of function, if conducted with a structured, standardized format, yields data with considerable reliability and validity.