A preliminary psychometric analysis of the Functional Outcome Profile (FOP)
Date
2007-04-20T18:56:54Z
Authors
Price, John Ryan
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Abstract
Few authors report comprehensive psychometric data for their acquired brain injury (ABI) outcome indices (e.g., items analyses, test-retest reliability, survivor-proxy agreement, internal consistency, convergent validity). Even fewer authors submit their indices to modern psychometric analyses, like Rasch analysis. The purpose of this dissertation was to evaluate the traditional and modern psychometric properties of a new index of brain injury outcome: the Functional Outcome Profile (FOP). One hundred and thirteen mixed (estimated mild, moderate, and severe injury) ABI survivors and 22 significant others participated in the study. Items analyses (n = 113) revealed that all items were endorsed by at least one ABI survivor, suggesting that the FOP assessed areas relevant to ABI survivors. However most items, composite scores, and the total score had distributions that were negatively skewed. One-week test-retest reliability correlations for the total score, composites, and items (n = 25) were generally in the moderate to strong range (r > 0.7), while survivor-proxy agreement correlations for the items (n = 22) were generally in the moderate range (r = 0.5 to 0.7). The internal consistency scores (n = 113) for 5 of the 8 composite scales and for the full FOP were good (Cronbach α > 0.7). Concurrent-convergent validity analyses revealed that the FOP correlated moderately well with the Mayo-Portland Adaptability Index (MPAI-4) (r = -0.75), but that it did not correlate with injury-related information (e.g., age at injury, time since injury, estimated severity). Rasch calibration of the FOP resulted in a 62-item index that fit the Rasch model well and that demonstrated good reliability and separation. Overall, the results suggest that the FOP has good traditional and modern psychometric properties when used with community-based outpatient ABI survivors. Future studies with the FOP should focus on improving the FOP’s clinical utility and further verifying its convergent and divergent validity.
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Keywords
acquired brain injury, outcome index, functional outcome