The psychometric properties of the Physical Resilience Instrument for Older Adults (PRIFOR): a Rasch analysis

Background: Prior psychometric evidence of the Physical Resilience Instrument for Older Adults (PRIFOR) showed good criterion-related validity, concurrent validity, known-group validity, predictive validity, and internal consistency. However, it is unclear whether older patients with different treatment diagnoses interpret the PRIFOR similarly. Aims: This study aimed to test the psychometric properties of the PRIFOR scores among different treatment diagnoses of older patients. Methods: We recruited 413 hospitalized older patients with a medical diagnosis and 207 with a surgical diagnosis in a 1343-bed tertiary-care medical center in Taiwan. Data analyses included Rasch models, Principal Components Analysis (PCA), and Pearson correlations. Results: The Rasch analyses showed that all PRIFOR items were embedded within their belonged constructs, reflecting good construct validity and unidimensionality. Person and item separation reliability support the internal consistency of the studied samples and PRIFOR items. However, six PRIFOR items were found to have meaningful differential item functioning (DIF) problems among treatment diagnoses. Conclusions: The PRIFOR is a solid measurement and can be used for monitoring the status of older adults’ physical resilience. However, because six items were found to have meaningful DIF among treatment diagnosis groups, future studies should consider designing specific items for different patient populations to assess their needs in physical resilience.