Measurement equivalence in ADL and IADL difficulty across international surveys of aging: findings from the HRS, SHARE, and ELSA.

TitleMeasurement equivalence in ADL and IADL difficulty across international surveys of aging: findings from the HRS, SHARE, and ELSA.
Publication TypeJournal Article
Year of Publication2012
AuthorsChan, KS, Kasper, JD, Brandt, J, Pezzin, LE
JournalJ Gerontol B Psychol Sci Soc Sci
Volume67
Issue1
Pagination121-32
Date Published2012 Jan
ISSN Number1758-5368
KeywordsActivities of Daily Living, Aged, Aged, 80 and over, Aging, Bias, Europe, Female, Health Surveys, Humans, Internationality, Longitudinal Studies, Male, United States
Abstract

<p><b>OBJECTIVE: </b>To examine the measurement equivalence of items on disability across three international surveys of aging.</p><p><b>METHOD: </b>Data for persons aged 65 and older were drawn from the Health and Retirement Survey (HRS, n = 10,905), English Longitudinal Study of Aging (ELSA, n = 5,437), and Survey of Health, Ageing and Retirement in Europe (SHARE, n = 13,408). Differential item functioning (DIF) was assessed using item response theory (IRT) methods for activities of daily living (ADL) and instrumental activities of daily living (IADL) items.</p><p><b>RESULTS: </b>HRS and SHARE exhibited measurement equivalence, but 6 of 11 items in ELSA demonstrated meaningful DIF. At the scale level, this item-level DIF affected scores reflecting greater disability. IRT methods also spread out score distributions and shifted scores higher (toward greater disability). Results for mean disability differences by demographic characteristics, using original and DIF-adjusted scores, were the same overall but differed for some subgroup comparisons involving ELSA.</p><p><b>DISCUSSION: </b>Testing and adjusting for DIF is one means of minimizing measurement error in cross-national survey comparisons. IRT methods were used to evaluate potential measurement bias in disability comparisons across three international surveys of aging. The analysis also suggested DIF was mitigated for scales including both ADL and IADL and that summary indexes (counts of limitations) likely underestimate mean disability in these international populations.</p>

Notes

The journals of gerontology. Series B, Psychological sciences and social sciences J Gerontol B Psychol Sci Soc Sci. 2011 Dec 12.

DOI10.1093/geronb/gbr133
User Guide Notes

http://www.ncbi.nlm.nih.gov/pubmed/22156662?dopt=Abstract

Endnote Keywords

measurement/SHARE/ELSA_/Activities Of Daily Living/instrumental activities of daily living/DISABILITY/DISABILITY/differential item functioning/differential item functioning

Endnote ID

62674

Alternate JournalJ Gerontol B Psychol Sci Soc Sci
Citation Key7623
PubMed ID22156662
PubMed Central IDPMC3267026
Grant ListAG032502 / AG / NIA NIH HHS / United States