Item and Scale Differential Functioning of the Mini-Mental State Exam Assessed Using the Differential Item and Test Functioning (DFIT) Framework

Published in: Medical Care, v. 44, no. 11, suppl. 3, Nov. 2006, p. S143-S151

Posted on on January 01, 2006

by Leo S. Morales, Claudia Flowers, Peter R. Gutierrez, Marjorie Kleinman, Jeanne A. Teresi

Read More

Access further information on this document at

This article was published outside of RAND. The full text of the article can be found at the link above.

OBJECTIVES: To illustrate the application of the Differential Item and Test Functioning (DFIT) method using English and Spanish versions of the Mini-Mental State Examination (MMSE). SUBJECTS: Study participants were 65 years of age or older and lived in North Manhattan, New York. Of the 1578 study participants who were administered the MMSE 665 completed it in Spanish. MEASURES: The MMSE contains 20 items that measure the degree of cognitive impairment in the areas of orientation, attention and calculation, registration, recall and language, as well as the ability to follow verbal and written commands. RESEARCH DESIGN: After assessing the dimensionality of the MMSE scale, item response theory person and item parameters were estimated separately for the English and Spanish sample using Samejima's 2-parameter graded response model. Then the DFIT framework was used to assess differential item functioning (DIF) and differential test functioning (DTF). RESULTS: Nine items were found to show DIF; these were items that ask the respondent to name the correct season, day of the month, city, state, and 2 nearby streets, recall 3 objects, repeat the phrase no ifs, no ands, no buts, follow the command, close your eyes, and the command, take the paper in your right hand, fold the paper in half with both hands, and put the paper down in your lap. At the scale level, however, the MMSE did not show differential functioning. CONCLUSIONS: Respondents to the English and Spanish versions of the MMSE are comparable on the basis of scale scores. However, assessments based on individual MMSE items may be misleading.

This report is part of the RAND Corporation External publication series. Many RAND studies are published in peer-reviewed scholarly journals, as chapters in commercial books, or as documents published by other organizations.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.