Differential item functioning for polytomous response items. Racialethnic differences in responses to the everyday discrimination scale. This statistical procedure, developed by ets researchers dorans and kulick 1983, is based on the computation of expected scores for the focal and reference groups. It is also germane to consider how the individual itemlevel dif indices aggregate across all n items of the test, referred to as differential test functioning dtf. Potential sources of differential item functioning in the adaptation of tests paula elosua and alicia lopezjauregui department of psychology university of the basque country, spain this report shows a classification of differential item functioning dif sources that have an effect on the adaptation of tests.
The sample consisted of 1,579 caucasians 1,023 men, 556 women and 523 blacks 321 men, 202 women who were applying for entrylevel, unskilled jobs in factories. Differential test functioning and dif effect variance. Assessing dif helps to understand the nature of instruments, to assess the quality of a measure and to interpret results. Differential item functioning dif is a statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Identifying race and gender differential item functioning among juvenile offenders. Differential item functioning columbia university mailman. Gibbons, phd, lance jolley, ms, and gerald van belle, phd introduction. This article has been cited by other articles in pmc. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the. The methods described thus far have addressed the concept of fairness and bias at the item level. A general framework and an r package for the detection of. Differential item functioning by sex and race in the hogan. Pdf on jul 19, 2018, alireza ahmadi and others published differential item functioning find, read and cite all the research you need on researchgate. Differential item functioning 2nd edition 9781412954945.
More specifically, an item is considered to be biased if two conditions are met. Lewis, department of epidemiology and public health, yale university school of medicine, 60 college street, 4th floor, new haven, ct 06520 email. In a classic article, aldrich and mckelvey introduce a method adjusting for such differential item functioning by assuming that all respondents perceive political stimuli identically. Pdf differential item functioning dif has been increasingly. Pdf an introduction to differential item functioning. Thus, differentially functioning items elicit different. As demonstration, a dataset from a 40item math test in a statewide testing program is analyzed by two widely. This is the webpage for the handbook on differential item functioning. Measurement invariance and differential item functioning. An item is labeled as having dif when people with the. Detection of differential item functioning dif by use of the logistic. Logistic regression modeling as a unitary framework for binary and likerttype ordinal item scores. The dif free thendif dftd strategy consists of two steps.
In the context of tests, dif occurs when people from different groups with the same ability have systematically different responses to speci. Sep 01, 2017 this is the webpage for the handbook on differential item functioning. Differential item functioning dif refers to group differences in performance on a test item that cannot be explained by group differences in the construct targeted. Tests for dif compare two or more groups of interest. Pdf download differential item functioning read online. Download differential item functioning ebook online. We analyzed 95 cognitive reading items, administered to students in 29 european countries. Differential item functioning research papers academia.
An introduction to differential item functioning analysis eric. For these items, a moderately positive relationship existed between item difficulty and the differential item functioning statistic, showing that black examinees performed. Item response theory detects differential item functioning. Item response theory detects differential item functioning between healthy and ill children in qol measures. Figure 1 displays a scatterplot for the males and females item difficulties.
The textbook is focused on item response theory overall, but discusses differential item functioning and item bias. Differential item functioning for minority examinees on. The 9item adolescent antisocial behavior scale had a dtf value of. Detection of crossing differential item functioning. Pdf differential item functioning dif is a key component in the. Assessment of differential item functioning in the perceived. The use of the term bias refers to various contexts, both statistical and social. Paper 29002015 multiple ways to detect differential item. The use of new item formats, new item types, and new test. We present an ordinal logistic regression model for identi. Assessment of differential item functioning in the. Estimating individuals political perceptions while. The purpose of the present analysis is to use differential item functioning dif to identify differences in the performance of native and immigrant students in pisa 2009 that can be directly related to their responses to particular items. For differential item functioning dif, the item response theory likelihood ratio test approach irtlr.
Dif threatens precise interpretations of survey results and makes them unreliable. Lewis, a note on the value of including the studied item in the test score when analyzing test items for dif. If the factor bringing about such a difference is not part of the construct of focus in the test, then the test would be biased. The full text of this article is available as a pdf. A handbook on the theory and methods of differential item functioning dif. Differential item functioning analysis with ordinal. Dec 24, 2015 pdf download differential item functioning read online. Differential item functioning analysis with ordinal logistic regression techniques difdetect and difwithpar paul k.
A more robust method for evaluating itemlevel bias is to test for differential item functioning dif, which takes into account differences at every level of candidate ability 16, 17. Differential item functioning dif is when a test item favors or hinders a characteristic exhibited by group members of a testtaking population. Differential item functioning sage research methods. Differential item functioning test fairness is a moral imperative for both the makers and the users of tests. Differential item functioning dif has been widely used in healthcare, business management, and educational measurement. The full text of this article is available as a pdf 95k. Differential item functioning dif has been increasingly applied in fairness studies in psychometric circles. Measuring differential item and test functioning across. Several methods have been proposed in recent decades for identifying items that function differently between two or more groups of examinees.
Correlations between item difficulty and differential item functioning were generally low, with the exception of quantitative items in the blackwhite analyses. Save up to 80% by choosing the etextbook option for isbn. Starting from a framework for classifying dif detection methods and from a comparative overview of the most traditional methods. Dif analysis investigates a differential characteristic of a test item between subpopulations of examinees and is useful in detecting possibly biased items toward a particular subpopulation. Dif analyses are statistical procedures used to determine to what extent the content of an item affects the item endorsement of subgroups of testtakers. An item displays dif when test takers possessing the same amount of an ability or trait, but belonging to different subgroups, do not share the same likelihood of correctly answering the item. Assessment developers design and construct questionnaires or tests including sets of items that measure, for example, cognition, personality traits, or political views. Differential item functioning for minority examinees on the. First, performance on the item is influenced by sources other than differences on the construct of interest that are deemed to be detrimental to one group. Item response modeling allows us to examine the likelihood that a particular symptom will be reported at a particular level of depression severity i. A statistic for testing the hypothesis of no dif is developed.
In order to estimate differential item functioning dif in bipolar versus unipolar depression, a twoparameter item response model was used. We provide a tutorial on differential item functioning dif analysis, an analytic. Starting from a framework for classifying dif detection methods and from a comparative overview of the most traditional methods, an r. The empirical evidence on differential item functioning presented in free dles article was obtained using the standardization approach. A logistic regression model for characterizing differential item functioning dif between two groups is presented. This study aimed to examine whether the items of the quality of life enjoyment and satisfaction. Differential item functioning dif of sf12 and qlesqsf. Pdf on jan 1, 2012, mohammad salehi and others published differential item functioning find, read and cite all the research you need on researchgate. Differential item functioning dif is an important issue of interest in psychometrics and educational measurement. Table 30 supports the investigation of item bias, differential item functioning dif, i.
Detecting differential item functioning using logistic. Recommendations for conducting differential item functioning. Using differential item functioning to evaluate potential. The assessment of differential item functioning dif has become an integral part of determining the validity of standardized tests and multiitem surveys. X fits an item response model when x are item scores e. Differential item functioning dif means the interference of some demographic characteristic or grouping of the tight relationship between trait levels. Differential item functioning in online learning instrument. If dif is found for many items on the test, the final test scores do not represent the same. Pdf download for detection of uniform and nonuniform differential item. Differential item functioning on antisocial behavior scale. Introduction essentially the same differential item functioning dif procedures have been used in practice since the late 1980s. Pdf an introduction to differential item functioning researchgate. Dorans, evaluating hypotheses about differential item functioning.
Judicious application of this methodology by the researchers, however, requires an. Assessment of differential item functioning in the perceived stress scale10. Differential item functioning 2nd edition by steven j. In brief, differential item functioning dif occurs when groups such as defined by gender, ethnicity, age, or education have different probabilities of endorsing a given item on a multi item scale after controlling for overall scale scores. Apr 12, 20 differential item functioning dif is when a test item favors or hinders a characteristic exhibited by group members of a testtaking population. Measures of differential item functioning dif are used at educational. A rasch differential item functioning analysis of the massachusetts youth screening instrument. But measuring these perceptions is difficult in part because respondents may use survey response scales in different ways. An item is considered to be biased if the item unfairly favors one group over another. Differential item functioning dif analysis is a key component in the evaluation of the fairness and validity of educational tests. Approaches for investigating how features s influence y are investigating item bias 21, differential item functioning dif 12 and measurement invariance 26.
Ensuring taiwan patient safety culture survey is free from. Educational and psychological measurement, 66, 502521. Racialethnic differences in responses to the everyday. Item response theory analysis and differential item. Detection of uniform and nonuniform differential item functioning. Judicious application of this methodology by the researchers, however, requires an understanding of the technical complexities involved. Differential item functioning dif is the preferred psychometric term for what is otherwise known as item bias. This article provides a brief primer overview of differential item functioning dif analysis. The authors examined measurement bias in the hogan personality inventory by investigating differential item functioning dif across sex and two racial groups caucasian and black. It highlights methods for testing test items that function differently for different groups. Eqs structural equations program manual encino, ca.
Vote instead for economic growth and free enterprise. Differential item functioning for polytomous response. The first step was to identify a group of dif free anchor items that could be used to link the two participants groups in terms of their ability. Differential item functioning dif is investigated to ensure that each item displays a consistent pattern of responses irrespective of the characteristics of the respondents. Burton, the effect of item screening on test scores and test characteristics. Potential sources of differential item functioning in the.
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