OBJECTIVE: To provide evidence of construct validity for the FIM instrument in the inpatient rehabilitation burn population. DESIGN: Confirmatory factor analysis and item response theory were used to assess construct validity. Confirmatory factor analysis was performed on a 2-factor model of the FIM instrument and on a 6-subfactor model. Mokken scale analysis, a nonparametric item response theory, was performed on each of the FIM instrument's 2 major factors, motor and cognitive domains. Internal consistency using Cronbach alpha and Molenaar and Sijtsma's statistic was also examined. SETTING: Inpatient rehabilitation facilities. PARTICIPANTS: Data from the Uniform Data System for Medical Rehabilitation for patients with an impairment code of burn injury from the years 2002 to 2011 were used for this analysis. A total of 7569 subjects were included in the study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Comparative fit index results for the confirmatory factor analyses and adherence to assumptions of the Mokken scale model. RESULTS: Confirmatory factor analysis provided a comparative fit index of .862 for the 2-factor model and .941 for the 6-subfactor model. Mokken scale analysis showed scalability coefficients of .681 and .891 for the motor and cognitive domains, respectively. Measures of internal consistency statistic gave values of >.95 for each major domain of the FIM instrument. CONCLUSIONS: The FIM instrument has evidence of validity and reliability as an outcome measure for patients with burn injuries in the inpatient rehabilitation setting. The 6-subfactor model provides a better fit than the 2-factor model by confirmatory factor analysis. There is evidence that the motor and cognitive domains each form valid unidimensional metrics based on nonparametric item response theory.
OBJECTIVE: To provide evidence of construct validity for the FIM instrument in the inpatient rehabilitation burn population. DESIGN: Confirmatory factor analysis and item response theory were used to assess construct validity. Confirmatory factor analysis was performed on a 2-factor model of the FIM instrument and on a 6-subfactor model. Mokken scale analysis, a nonparametric item response theory, was performed on each of the FIM instrument's 2 major factors, motor and cognitive domains. Internal consistency using Cronbach alpha and Molenaar and Sijtsma's statistic was also examined. SETTING: Inpatient rehabilitation facilities. PARTICIPANTS: Data from the Uniform Data System for Medical Rehabilitation for patients with an impairment code of burn injury from the years 2002 to 2011 were used for this analysis. A total of 7569 subjects were included in the study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Comparative fit index results for the confirmatory factor analyses and adherence to assumptions of the Mokken scale model. RESULTS: Confirmatory factor analysis provided a comparative fit index of .862 for the 2-factor model and .941 for the 6-subfactor model. Mokken scale analysis showed scalability coefficients of .681 and .891 for the motor and cognitive domains, respectively. Measures of internal consistency statistic gave values of >.95 for each major domain of the FIM instrument. CONCLUSIONS: The FIM instrument has evidence of validity and reliability as an outcome measure for patients with burn injuries in the inpatient rehabilitation setting. The 6-subfactor model provides a better fit than the 2-factor model by confirmatory factor analysis. There is evidence that the motor and cognitive domains each form valid unidimensional metrics based on nonparametric item response theory.
Authors: Olivia R Stockly; Audrey E Wolfe; Richard Goldstein; Kimberly Roaten; Shelley Wiechman; Nhi-Ha Trinh; Jeremy Goverman; Frederick J Stoddard; Ross Zafonte; Colleen M Ryan; Jeffrey C Schneider Journal: J Burn Care Res Date: 2022-07-01 Impact factor: 1.819