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Activity Number:
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148
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Type:
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Contributed
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Date/Time:
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Monday, July 30, 2007 : 10:30 AM to 12:20 PM
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Sponsor:
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Section on Health Policy Statistics
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| Abstract - #308244 |
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Title:
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Distribution of Cronbach's Alpha for Ordinal Data: A Bayesian-Based Approach
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Author(s):
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Byron Gajewski*+ and Diane K. Boyle and Sarah Thompson
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Companies:
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The University of Kansas Medical Center and The University of Kansas Medical Center and University of Nebraska Medical Center
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Address:
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3901 Rainbow Blvd, Kansas City, KS, 66160,
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Keywords:
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Confidence intervals ; Credible intervals ; latent variables ; psychometric evaluation ; item response models ; multivariate normal distribution
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Abstract:
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We propose point estimates and intervals for Cronbach's alpha when the data are ordinal. Traditional calculations of Cronbach's alpha on ordinal instruments underestimate the true Cronbach's alpha provided from the latent variables that are assumed to produce the ordinal data. By utilizing Bayesian models and multiple imputation, confidence (credible) intervals are provided for Cronbach's alpha at the latent variable level. The proposed methodology is shown to have theoretically correct coverage probability and is demonstrated on an instrument that measures nursing home residents' quality of life.
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