Activity Number:
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169
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Type:
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Topic Contributed
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Date/Time:
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Tuesday, August 13, 2002 : 8:30 AM to 10:20 AM
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Sponsor:
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Section on Health Policy Statistics*
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Abstract - #301643 |
Title:
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Defining and Measuring Primary Dimensions of Self-reported Health: An IRT Approach to Item Banking and Computerized Adaptive Testing
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Author(s):
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Chih-Hung Chang*+ and David Cella
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Affiliation(s):
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Evanston Northwestern Healthcare and Evanston Northwestern Healthcare
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Address:
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1001 University Place, Suite 100, Evanston, Illinois, 60201, USA
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Keywords:
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health status assessment ; item response theory ; rating scale model ; partial credit model ; item bank ; computerized adaptive testing
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Abstract:
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OBJECTIVE: This study illustrates a method for understanding the extent to which a large pool of health status questions can be examined for their primary dimensionality. SAMPLE: We simultaneously administered five questionnaires to 1,714 people with cancer and HIV disease. METHODS: We used item response theory (IRT)-based approaches that combined rating scale model and partial credit model. ANALYSES: Item responses were co-calibrated onto one presumed underlying construct. To identify significant, primary sub-structures in the data, we then conducted a factor analysis of the data residuals to determine the dimensional pattern of any deviation from unidimensionality. RESULTS: Two definable primary dimensions were derived: Physical well-being and mental well-being. Item banks were then established and computerized adaptive testing platform developed. CONCLUSIONS: These results provide direction for further defining these dimensions, so they can be measured more precisely and consistently. The delivery of precise and ready-to-use health status information for both patients and clinicians during office visits allows for better-informed treatment planning in clinical practice.
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