Abstract
Objective: The Multidimensional Health Locus of Control (MHLC) scales are widely used to measure beliefs about determinants of persons' health. We evaluated the scales over the largest-ever disease-specific sample of subjects using a combined-method psychometric approach. Study Design and Setting: We performed a secondary analysis of data from 1,206 subjects from three osteoarthritis studies, using Rasch analysis and confirmatory factor analysis simultaneously. Differential item functioning (DIF) by gender and data source, scale dimensionality, and item fit were examined. The Rasch model fit the data if Rasch residual principal components analysis (PCA) corroborated three distinct dimensions and item fit statistics fell between 0.80 and 1.20. The confirmatory factor (CFA) model fit the data if factor loadings exceeded 0.50 for all items. Results: DIF by gender or data source was not materially evident for any items. PCA supported existence of three dimensions in the data. Both Rasch and CFA models fit the data for 16 items; two items were detected as misperforming. When these items were removed, fit of both models improved. Conclusion: Results of this large-sample evaluation of the MHLC scales corroborated earlier findings that removal of certain items improves the scales. The combined Rasch-CFA approach provided better insight to scale performance problems than either method alone provided.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 440-447 |
| Number of pages | 8 |
| Journal | Journal of Clinical Epidemiology |
| Volume | 60 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2007 |
Funding
Support for study design, data collection, data analysis, and manuscript preparation was provided by the Agency for Healthcare Research and Quality, R01 AR-049999-04; the Agency for Healthcare Research and Quality and Office of Minority Health, National Institutes of Health, P01 HS-10876-04; and the Health Services Research and Development Service, U.S. Department of Veterans Affairs. Support for data collection was also provided by the Alberta Heritage Foundation for Medical Research, Alberta, Canada. Dr. Kelly is supported by a career development award from the Health Services Research and Development Service, U.S. Department of Veterans Affairs. The authors wish to thank Vanessa Cox for assistance with data analysis.
Keywords
- Factor analysis
- Health-related locus of control
- MHLC scales
- Measurement
- Osteoarthritis
- Rasch analysis
ASJC Scopus subject areas
- Epidemiology