How useful are the SF-36 sub-scales in older people? Mokken scaling of data from the HALCyon programme
How useful are the SF-36 sub-scales in older people? Mokken scaling of data from the HALCyon programme
Purpose: To evaluate two psychometric properties of SF-36, namely unidimensionality and reliability.
Methods: The data are from three cohorts in the HALCyon collaborative research programme into healthy ageing: Aberdeen Birth Cohort 1936 (n = 428), Hertfordshire Ageing Study (n = 358) and Hertfordshire Cohort Study (n = 3,216). The Mokken scaling model was applied to each sub-scale of SF-36 to evaluate unidimensionality as indicated by scalability. The lower bound for internal consistency reliability was determined by Cronbach’s alpha.
Results: All six sub-scales of SF-36, with the exception of general health (GH) and mental health (MH), demonstrated strong scalability (0.5 ? H < 1). The results were consistent across all 3 cohorts. Both GH and MH showed medium scalability (0.4 ? H <0.55), although individual items ‘sick easier..’, ‘as healthy as..’ and ‘expect to get worse’ of the GH sub-scale and ‘nervous’, ‘happy’ in the MH sub-scale had low scalability (H < 0.4) in the oldest cohort (aged 73–83). Cronbach’s alphas for all sub-scales were between 0.70 and 0.92.
Conclusions: The unidimensionality and reliability of the sub-scales of SF-36 are sufficient to make this a useful measure of health-related quality of life in older people. Caution is needed when interpreting the results for GH and MH in the oldest cohort due to the poor unidimensionality.
sf-36, psychometric properties, unidimensionality, reliability, cronbach’s alpha, mokken scaling
1005-1010
Mishra, Gita D.
02143b82-e536-4915-9b30-3c86cbe1a1fe
Gale, Catharine R.
5bb2abb3-7b53-42d6-8aa7-817e193140c8
Sayer, Avan Aihie
fb4c2053-6d51-4fc1-9489-c3cb431b0ffb
Cooper, Cyrus
e05f5612-b493-4273-9b71-9e0ce32bdad6
Dennison, Elaine M.
ee647287-edb4-4392-8361-e59fd505b1d1
Whalley, Lawrence J.
bf292f06-d800-4808-b589-df748448bb1b
Craig, Leone
ebc2fd1d-9230-4195-8e29-63424436d840
Kuh, Diana
4f3b51aa-21a0-4d68-be14-e1ed75448aaf
Deary, Ian J.
027158ae-fbfb-40ea-98b1-32d2690499ac
September 2011
Mishra, Gita D.
02143b82-e536-4915-9b30-3c86cbe1a1fe
Gale, Catharine R.
5bb2abb3-7b53-42d6-8aa7-817e193140c8
Sayer, Avan Aihie
fb4c2053-6d51-4fc1-9489-c3cb431b0ffb
Cooper, Cyrus
e05f5612-b493-4273-9b71-9e0ce32bdad6
Dennison, Elaine M.
ee647287-edb4-4392-8361-e59fd505b1d1
Whalley, Lawrence J.
bf292f06-d800-4808-b589-df748448bb1b
Craig, Leone
ebc2fd1d-9230-4195-8e29-63424436d840
Kuh, Diana
4f3b51aa-21a0-4d68-be14-e1ed75448aaf
Deary, Ian J.
027158ae-fbfb-40ea-98b1-32d2690499ac
Mishra, Gita D., Gale, Catharine R., Sayer, Avan Aihie, Cooper, Cyrus, Dennison, Elaine M., Whalley, Lawrence J., Craig, Leone, Kuh, Diana and Deary, Ian J.
,
HALCyon Study Team
(2011)
How useful are the SF-36 sub-scales in older people? Mokken scaling of data from the HALCyon programme.
Quality of Life Research, 20 (7), .
(doi:10.1007/s11136-010-9838-7).
(PMID:21225350)
Abstract
Purpose: To evaluate two psychometric properties of SF-36, namely unidimensionality and reliability.
Methods: The data are from three cohorts in the HALCyon collaborative research programme into healthy ageing: Aberdeen Birth Cohort 1936 (n = 428), Hertfordshire Ageing Study (n = 358) and Hertfordshire Cohort Study (n = 3,216). The Mokken scaling model was applied to each sub-scale of SF-36 to evaluate unidimensionality as indicated by scalability. The lower bound for internal consistency reliability was determined by Cronbach’s alpha.
Results: All six sub-scales of SF-36, with the exception of general health (GH) and mental health (MH), demonstrated strong scalability (0.5 ? H < 1). The results were consistent across all 3 cohorts. Both GH and MH showed medium scalability (0.4 ? H <0.55), although individual items ‘sick easier..’, ‘as healthy as..’ and ‘expect to get worse’ of the GH sub-scale and ‘nervous’, ‘happy’ in the MH sub-scale had low scalability (H < 0.4) in the oldest cohort (aged 73–83). Cronbach’s alphas for all sub-scales were between 0.70 and 0.92.
Conclusions: The unidimensionality and reliability of the sub-scales of SF-36 are sufficient to make this a useful measure of health-related quality of life in older people. Caution is needed when interpreting the results for GH and MH in the oldest cohort due to the poor unidimensionality.
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Published date: September 2011
Keywords:
sf-36, psychometric properties, unidimensionality, reliability, cronbach’s alpha, mokken scaling
Organisations:
Faculty of Medicine
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Local EPrints ID: 196099
URI: http://eprints.soton.ac.uk/id/eprint/196099
ISSN: 0962-9343
PURE UUID: a4d8f60e-cc48-4863-8eb6-62f4995d9d1c
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Date deposited: 28 Sep 2011 14:01
Last modified: 18 Mar 2024 02:45
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Author:
Gita D. Mishra
Author:
Avan Aihie Sayer
Author:
Lawrence J. Whalley
Author:
Leone Craig
Author:
Diana Kuh
Author:
Ian J. Deary
Corporate Author: HALCyon Study Team
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