Identification of differential item functioning using item response theory and the likelihood-based model comparison approach. Application to the Mini-Mental State Examination.
BACKGROUND
An important part of examining the adequacy of measures for use in ethnically diverse populations is the evaluation of differential item functioning (DIF) among subpopulations such as those administered the measure in different languages. A number of methods exist for this purpose.


OBJECTIVE
The objective of this study was to introduce and demonstrate the identification of DIF using item response theory (IRT) and the likelihood-based model comparison approach.


METHODS
Data come from a sample of community-residing elderly who were part of a dementia case registry. A total of 1578 participants were administered either an English (n = 913) or Spanish (n = 665) version of the 21-item Mini-Mental State Examination. IRT was used to identify language DIF in these items with the likelihood-based model comparison approach.


RESULTS
: Fourteen of the 21 items exhibited significant DIF according to language of administration. However, because the direction of the identified DIF was not consistent for one language version over the other, the impact at the scale level was negligible.


CONCLUSIONS
IRT and the likelihood-based model comparison approach comprise a powerful tool for DIF detection that can aid in the development, refinement, and evaluation of measures for use in ethnically diverse populations.
Orlando Edelen
Maria Orlando
MO
RAND Corporation, Santa Monica, California 90407, USA. maria_orlando@rand.org
Thissen
David
D
Teresi
Jeanne A
JA
Kleinman
Marjorie
M
Ocepek-Welikson
Katja
K
D000368:Aged; D015982:Bias; D003431:Cross-Cultural Comparison; D003627:Data Interpretation, Statistical; D003704:Dementia / Q000175:diagnosis* / Q000208:ethnology; D005006:Ethnicity / Q000523:psychology / Q000706:statistics & numerical data; D005260:Female; D006630:Hispanic or Latino / Q000523:psychology* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000592:standards; D009519:New York City; D011594:Psychometrics / Q000379:methods*; D012015:Reference Standards; D014175:Translating