The Functional Independence Measure 18-item version can be reported as a unidimensional interval-scaled metric: Internal construct validity revisited

Abstract

Baseline analysis and the traditional testlet approach showed no fit with the Rasch model. When items were grouped into 2 testlets, fit to the Rasch model was achieved, indicating unidimensionality across all 18 items. A transformation table to convert FIM™ raw ordinal scores to the corresponding Rasch interval scaled values was created. Conclusion: This study provides evidence that FIM™ total scores represent a unidimensional set of items, supporting their use in clinical practice and outcome reporting when applying the respective transformation table. This provides a basis for standardized reporting of functioning.

Examining the complexity of functioning in persons with spinal cord injury attending first rehabilitation in Switzerland using structural equation modelling

“…If items showed local dependence, a testlet approach was used to introduce super-items created by summing the initial response options of local dependent items. The corresponding analysis approach is described elsewhere [25].…”

Can Multidisciplinary Inpatient and Outpatient Rehabilitation Provide Sufficient Prevention of Disability in Patients with a Brain Tumor?—A Case-Series Report of Two Programs and A Prospective, Observational Clinical Trial

“…The Functional Independence Measure (FIM) is a measurement scale that explores an individual's physical, psychological, and social functioning [15]. There are 18 items within the FIM.…”

“…Each item is rated on a scale of 1 to 7 (1-total assistance, 7-independence). The score shows a participant's dependency in each area measured [15]. If the score falls below 6, another person is required for assistance or supervision.…”

“…The FIM is extensively used to assess patients' level of disability as well as changes in patient status in response to rehabilitation or medical intervention, also among patients with BT [15,16]. The tool is used to evaluate how well a person can carry out daily life activities and, thus, how dependent the patient would be on others [15]. By adding the points for each item, the possible total score ranges from 18 (lowest) to 126 (highest) levels of independence.…”

“…By adding the points for each item, the possible total score ranges from 18 (lowest) to 126 (highest) levels of independence. During rehabilitation, admission, and discharge, scores are rated by a multidisciplinary rehabilitation team while observing patients' functioning [15].…”