title: Identification of differential item functioning using item response theory and the likelihood-based model comparison approach. Application to the Mini-Mental State Examination.
abstract: 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.
authors.affiliation: RAND Corporation, Santa Monica, California 90407, USA. maria_orlando@rand.org
authors.forename: Maria Orlando
authors.initials: MO
authors.lastname: Orlando Edelen
authors.forename: David
authors.initials: D
authors.lastname: Thissen
authors.forename: Jeanne A
authors.initials: JA
authors.lastname: Teresi
authors.forename: Marjorie
authors.initials: M
authors.lastname: Kleinman
authors.forename: Katja
authors.initials: K
authors.lastname: Ocepek-Welikson
mesh_terms: 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