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Differential Item (differential + item)

Distribution by Scientific Domains
Medical Sciences50%

Terms modified by Differential Item

  • differential item functioning
    		•

    Selected Abstracts

    Identifying Sources of Differential Item and Bundle Functioning on Translated Achievement Tests: A Confirmatory Analysis

    JOURNAL OF EDUCATIONAL MEASUREMENT, Issue 2 2001
    Mark J. Gierl
    Increasingly, tests are being translated and adapted into different languages. Differential item functioning (DIF) analyses are often used to identify non-equivalent items across language groups. However, few studies have focused on understanding why some translated items produce DIF. The purpose of the current study is to identify sources of differential item and bundle functioning on translated achievement tests using substantive and statistical analyses. A substantive analysis of existing DIF items was conducted by an 11-member committee of testing specialists. In their review, four sources of translation DIF were identified. Two certified translators used these four sources to categorize a new set of DIF items from Grade 6 and 9 Mathematics and Social Studies Achievement Tests. Each item was associated with a specific source of translation DIF and each item was anticipated to favor a specific group of examinees. Then, a statistical analysis was conducted on the items in each category using SIBTEST. The translators sorted the mathematics DIF items into three sources, and they correctly predicted the group that would be favored for seven of the eight items or bundles of items across two grade levels. The translators sorted the social studies DIF items into four sources, and they correctly predicted the group that would be favored for eight of the 13 items or bundles of items across two grade levels. The majority of items in mathematics and social studies were associated with differences in the words, expressions, or sentence structure of items that are not inherent to the language and/or culture. By combining substantive and statistical DIF analyses, researchers can study the sources of DIF and create a body of confirmed DIF hypotheses that may be used to develop guidelines and test construction principles for reducing DIF on translated tests. [source]

    Assessing autonomic symptoms of Parkinson's disease with the SCOPA-AUT: a new perspective from Rasch analysis

    EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2010
    M. J. Forjaz
    Background:, The Scale for Outcomes in Parkinson's disease (PD) for Autonomic Symptoms (SCOPA-AUT) is a specific scale to assess autonomic dysfunction in PD patients. It was developed and validated under the classic test theory approach. This study sought to test whether the SCOPA-AUT meets item response theory standards for reliability, internal construct validity, response category ordering, and differential item functioning by gender and age group. Method:, The Rasch measurement model was applied to a sample of 385 PD patients. Results:, Model fit was obtained after the response categories were rescored and item 10-Incomplete emptying deleted because of redundancy. Person separation index, a reliability measure, was 0.82. All but two items (2-Sialorrhea and 13-Nocturia) were free of gender- and age-related bias. The strict tests of unidimensionality were met, indicating the validity of the total sumscore. Scale targeting suggested the need for items representing milder autonomic symptoms. Conclusions:, Suggestions for improving the SCOPA-AUT include a shorter scale with a simpler response scheme and a combination of sexual items for men and women. The resulting SCOPA-AUT is a reliable scale, with good internal construct validity, providing Rasch transformed results on a linear metric scale. [source]

    Identifying Sources of Differential Item and Bundle Functioning on Translated Achievement Tests: A Confirmatory Analysis

    JOURNAL OF EDUCATIONAL MEASUREMENT, Issue 2 2001
    Mark J. Gierl
    Increasingly, tests are being translated and adapted into different languages. Differential item functioning (DIF) analyses are often used to identify non-equivalent items across language groups. However, few studies have focused on understanding why some translated items produce DIF. The purpose of the current study is to identify sources of differential item and bundle functioning on translated achievement tests using substantive and statistical analyses. A substantive analysis of existing DIF items was conducted by an 11-member committee of testing specialists. In their review, four sources of translation DIF were identified. Two certified translators used these four sources to categorize a new set of DIF items from Grade 6 and 9 Mathematics and Social Studies Achievement Tests. Each item was associated with a specific source of translation DIF and each item was anticipated to favor a specific group of examinees. Then, a statistical analysis was conducted on the items in each category using SIBTEST. The translators sorted the mathematics DIF items into three sources, and they correctly predicted the group that would be favored for seven of the eight items or bundles of items across two grade levels. The translators sorted the social studies DIF items into four sources, and they correctly predicted the group that would be favored for eight of the 13 items or bundles of items across two grade levels. The majority of items in mathematics and social studies were associated with differences in the words, expressions, or sentence structure of items that are not inherent to the language and/or culture. By combining substantive and statistical DIF analyses, researchers can study the sources of DIF and create a body of confirmed DIF hypotheses that may be used to develop guidelines and test construction principles for reducing DIF on translated tests. [source]

    A Rasch Model Analysis of Alcohol Consumption and Problems Across Adolescence and Young Adulthood

    ALCOHOLISM, Issue 4 2009
    Christopher W. Kahler
    Background:, Recent investigations using item response modeling have begun to conceptualize alcohol consumption, problems, and dependence as representing points along a single continuum of alcohol involvement. Such a conceptualization may be of particular benefit to measurement of alcohol involvement in adolescents, but investigations to date have been limited to adult samples and may not generalize to adolescents due to age-related developmental differences. Methods:, This study used Rasch model analyses to examine the properties of indices of alcohol consumption and problems among 6,353 adolescents, aged 12 to 18 years, in Wave 1 of the Add Health survey. A particular focus was on whether the functioning of items changed when these adolescents were re-interviewed in Wave 3 when they were 18 to 24 years of age. Results:, Rasch model analyses supported the unidimensionality and additive properties of the items in the Wave 1 data. Comparisons of Wave 1 and Wave 3 data indicated differential item functioning in most of the items such that items related to alcohol consumption were more severe during adolescence, whereas items related to alcohol problems were more severe in young adulthood. Conclusions:, A valid index of alcohol involvement in adolescents can be constructed combining indices of alcohol consumption and alcohol problems. Such an index covers a range of severity and functions similarly across sex and race/ethnicity. A similar index can be constructed in young adulthood. However, the interpretation of scores must be attentive to developmental differences. In particular, for adolescents, indices of alcohol consumption are relatively closer in severity to indices of alcohol problems than they are among young adults. Thus, alcohol problems are more likely among adolescents than young adults given a similar level of drinking. [source]