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Construct validity of the SF-12 in three different samples.

Jakobsson, Ulf LU ; Westergren, Albert; Lindskov, Susanne and Hagell, Peter LU (2012) In Journal of Evaluation in Clinical Practice 18. p.560-566
Abstract
Rationale, aims and objectives Studies have challenged the validity and underlying measurement model of the physical and mental component summary scores of the 36-item Short-Form Health Survey in, for example the elderly and people with neurological disorders. However, it is unclear to what extent these observations translate to physical and mental component summary scores derived from the 12-item short form (SF-12) of the 36-item Short-Form Health Survey. This study evaluated the construct validity of the SF-12 in elderly people and people with Parkinson's disease (PD) and stroke. Methods SF-12 data from a general elderly (aged 75+) population (n = 4278), people with PD (n = 159) and stroke survivors (n = 89) were analysed regarding data... (More)
Rationale, aims and objectives Studies have challenged the validity and underlying measurement model of the physical and mental component summary scores of the 36-item Short-Form Health Survey in, for example the elderly and people with neurological disorders. However, it is unclear to what extent these observations translate to physical and mental component summary scores derived from the 12-item short form (SF-12) of the 36-item Short-Form Health Survey. This study evaluated the construct validity of the SF-12 in elderly people and people with Parkinson's disease (PD) and stroke. Methods SF-12 data from a general elderly (aged 75+) population (n = 4278), people with PD (n = 159) and stroke survivors (n = 89) were analysed regarding data quality, reliability (coefficient alpha) and internal construct validity. The latter was assessed through item-total correlations, exploratory and confirmatory factor analyses. Results Completeness of data was high (93-98.8%) and reliability was acceptable (0.78-0.85). Item-total correlations argued against the suggested items-to-summary scores structure in all three samples. Exploratory factor analyses failed to support a two-dimensional item structure among elderly and stroke survivors, and cross-loadings of items were seen in all three samples. Confirmatory factor analyses showed lack of fit between empirical data and the proposed items-to-summary measures structure in all samples. Conclusions These observations challenge the validity and interpretability of SF-12 scores among the elderly, people with PD and stroke survivors. The standard orthogonally weighted SF-12 scoring algorithm is cautioned against. Instead, when the assumed two-dimensional structure is supported in the data, oblique scoring algorithms appear preferable. Failure to consider basic scoring assumptions may yield misleading results. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Evaluation in Clinical Practice
volume
18
pages
560 - 566
publisher
Wiley-Blackwell
external identifiers
  • wos:000303807600008
  • pmid:21210901
  • scopus:84860875699
ISSN
1365-2753
DOI
10.1111/j.1365-2753.2010.01623.x
language
English
LU publication?
yes
id
4489d038-0357-495e-92ec-2277e330a058 (old id 1777752)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/21210901?dopt=Abstract
date added to LUP
2011-02-01 11:11:56
date last changed
2017-11-12 04:08:42
@article{4489d038-0357-495e-92ec-2277e330a058,
  abstract     = {Rationale, aims and objectives Studies have challenged the validity and underlying measurement model of the physical and mental component summary scores of the 36-item Short-Form Health Survey in, for example the elderly and people with neurological disorders. However, it is unclear to what extent these observations translate to physical and mental component summary scores derived from the 12-item short form (SF-12) of the 36-item Short-Form Health Survey. This study evaluated the construct validity of the SF-12 in elderly people and people with Parkinson's disease (PD) and stroke. Methods SF-12 data from a general elderly (aged 75+) population (n = 4278), people with PD (n = 159) and stroke survivors (n = 89) were analysed regarding data quality, reliability (coefficient alpha) and internal construct validity. The latter was assessed through item-total correlations, exploratory and confirmatory factor analyses. Results Completeness of data was high (93-98.8%) and reliability was acceptable (0.78-0.85). Item-total correlations argued against the suggested items-to-summary scores structure in all three samples. Exploratory factor analyses failed to support a two-dimensional item structure among elderly and stroke survivors, and cross-loadings of items were seen in all three samples. Confirmatory factor analyses showed lack of fit between empirical data and the proposed items-to-summary measures structure in all samples. Conclusions These observations challenge the validity and interpretability of SF-12 scores among the elderly, people with PD and stroke survivors. The standard orthogonally weighted SF-12 scoring algorithm is cautioned against. Instead, when the assumed two-dimensional structure is supported in the data, oblique scoring algorithms appear preferable. Failure to consider basic scoring assumptions may yield misleading results.},
  author       = {Jakobsson, Ulf and Westergren, Albert and Lindskov, Susanne and Hagell, Peter},
  issn         = {1365-2753},
  language     = {eng},
  pages        = {560--566},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Evaluation in Clinical Practice},
  title        = {Construct validity of the SF-12 in three different samples.},
  url          = {http://dx.doi.org/10.1111/j.1365-2753.2010.01623.x},
  volume       = {18},
  year         = {2012},
}