The Functional Independence Measure 18-item version can be reported as a unidimensional interval-scaled metric: Internal construct validity revisited
Autor: | Roxanne Maritz, Alan Tennant, Carolina Fellinghauer, Gerold Stucki, Birgit Prodinger |
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Jazyk: | angličtina |
Rok vydání: | 2019 |
Předmět: | |
Zdroj: | Journal of Rehabilitation Medicine, Vol 51, Iss 3, Pp 193-200 (2019) |
Druh dokumentu: | article |
ISSN: | 1650-1977 1651-2081 16501977 |
DOI: | 10.2340/16501977-2525 |
Popis: | Objective: Since the 1990s the Functional Independence Measure (FIM™) was believed to measure 2 different constructs, represented by its motor and cognitive subscales. The practice of reporting FIM™ total scores, together with recent developments in the understanding of the influence of locally dependent items on fit to the Rasch model, raises the question of whether the FIM™ 18-item version can be reported as a unidimensional interval-scaled metric. Design: Rasch analysis of the FIM™ using testlet approaches to accommodate local response dependency. Patients: A calibration sample containing 946 cases of data from 11,103 patients undergoing neurological or musculoskeletal rehabilitation in Switzerland in 2016. Results: 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. |
Databáze: | Directory of Open Access Journals |
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