References of "Magis, David"
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See detailLa correction d'indices de détection de patrons de réponses inappropriés paramétriques: une étude de type Monte Carlo
Béland, Sébastien; Raîche, Gilles; Magis, David ULg

Conference (2010, November)

L’une des conditions à respecter afin d’interpréter adéquatement les scores obtenus à un test est de s'assurer que les sujets ont répondu selon leur habileté réelle. Or, il se peut que certains individus ... [more ▼]

L’une des conditions à respecter afin d’interpréter adéquatement les scores obtenus à un test est de s'assurer que les sujets ont répondu selon leur habileté réelle. Or, il se peut que certains individus tentent de se surclasser en trichant ou de se sous-classer intentionnellement. Par chance, de nombreuses méthodes ont été développées pour détecter les individus qui adoptent de telles stratégies. Dans le cadre de cette présentation, nous nous intéresserons plus particulièrement aux indices de détection de patrons de réponses inappropriés. L’utilisation des indices de détection paramétriques comporte de nombreuses limites (Meijer et Sijtsma, 2001). Par exemple, nous savons que plusieurs indices ne peuvent pas être interprétés à partir des quantiles d’une loi de distribution connue. De plus, il est connu que l’utilisation d’une estimation de l’habileté peut grandement affecter la distribution connue de certains indices. Afin de dépasser les problèmes précédents, Snijders (2001) a développé une approche permettant de corriger les indices de détection de patrons de réponses inappropriés lorsqu'une estimation de l’habileté est considérée. Les indices ainsi corrigés suivent asymptotiquement une loi normale standard, ce qui permet la définition de seuils de détection de patrons inappropriés. Nous présenterons comment cette correction permet d'améliorer l'identification des patrons de réponses problématiques, notamment grâce à une diminution de l'écart entre l’erreur de type I empirique et le niveau de signification nominal. Une approche par simulation de données de type Monte Carlo sera présentée, et différents estimateurs de l'habileté (maximum de vraisemblance, maximum de vraisemblance a posteriori, maximum de vraisemblance pondérée) seront utilisés. [less ▲]

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See detailDes modèles psychométriques pour corriger les résultats dans des enquêtes malgré les tentatives de fraude
Raîche, Gilles; Béland, Sébastien; Magis, David ULg

Conference (2010, November)

Dans le contextes des enquêtes, il arrive fréquemment que les répondants ne fournissent pas nécessairement des réponses appropriées. C'est le cas notamment en ce qui a trait aux cas de fraudes dans les ... [more ▼]

Dans le contextes des enquêtes, il arrive fréquemment que les répondants ne fournissent pas nécessairement des réponses appropriées. C'est le cas notamment en ce qui a trait aux cas de fraudes dans les épreuves d'évaluation des habiletés disciplinaires. À cette fin, des modèles psychométriques ont été proposés pour corriger le résultat d'un étudiant malgré ses tentatives de fraudes. Ces modèles reposent toutefois uniquement sur des réponses de type dichotomique ou seulement une bonne ou une mauvaise réponse est considérée. Ces comportements de fraude sont également présents à l'intérieur des enquêtes d'opinion qui s'intéressent aux perceptions des répondants. La plupart du temps les réponses à ces enquêtes présentent plus d'un choix de réponses et sont alors dits polytomiques. Récemment, de nouvelles modélisations appropriées pour ce type de réponses ont été proposées. Elles seront présentées et accompagnées d'exemples d'application. [less ▲]

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See detailIdentification of differential item functioning by logistic regression: application to intellectual disability data
Magis, David ULg; Facon, Bruno

Conference (2010, October 14)

The purpose of this talk is to briefly present the logistic regression procedure to identify differential itm functioning (DIF) in psychometrics, and to illustrate the method on a practical data set about ... [more ▼]

The purpose of this talk is to briefly present the logistic regression procedure to identify differential itm functioning (DIF) in psychometrics, and to illustrate the method on a practical data set about intellectual disability. DIF is an important research fi eld and many statistical methods have been developed in this framework. Logistic regression has the asset of not being based on item response models, and it can detect both uniform and nonuniform DIF. In addition, it can be applied to the comparison of more than two groups. This method is illustrated by comparing two groups of French pupils, one group of normal ability students and one group with intellectually disabled students. Raven's Colored Progressive Matrices test is assigned and DIF is investigated between the two groups. It is concluded that none of the items can be flagged as functioning differently. [less ▲]

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See detailOld and new issues in differential item functioning (DIF): How to overcome current research conservatism?
Magis, David ULg

Scientific conference (2010, October 05)

In the context of differential item functioning (DIF), some issues have been pointed out more than 20 years ago, whereas other ones have appeared much more recently (often due to an incredible increase of ... [more ▼]

In the context of differential item functioning (DIF), some issues have been pointed out more than 20 years ago, whereas other ones have appeared much more recently (often due to an incredible increase of available information). In addition, there is some uprising evidence that the topic of DIF is becoming less attractive for journal editors. Explaining the reasons for this lack of interest in DIF, and why it should be actively countered, are the main goals of this talk. Three specific issues will be discussed: (a) the supremacy of the Mantel-Haenszel method, (b) the problem of item purification, and (c) the identification of DIF among multiple groups. Some recent and ongoing research results will be discussed to highlight why DIF should not be left alone in the years to come. [less ▲]

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See detailMultidimensional fluctuation, pseudo-guessing and carelessness IRT person parameters with polytomous item response models
Raîche, Gilles; Magis, David ULg; Béland, Sébastien

Conference (2010, July)

Frequently, candidates at aptitude multiple choice test miss attention, motivation or preparation and show underachievement or overachievement. Similarly, at surveys respondents show frequently misfitting ... [more ▼]

Frequently, candidates at aptitude multiple choice test miss attention, motivation or preparation and show underachievement or overachievement. Similarly, at surveys respondents show frequently misfitting patterns of responses. Their result does not correspond any more to their true aptitude or attitude, an inappropriate response pattern being obtained. New multidimensional models specific to polytomous responses circumvent these situations and diminish considerably the associated person bias. Multidimensional polytomous item response models adding new person parameters to the trait of the candidate are proposed. In the spirit of previous Raiche’s dichotomous responses IRT propositions, like the discrimination and don’t know item parameters, these models offer fluctuation and don’t know person parameters. Estimation methods, results from simulation showing the efficacy of these models and recommendations for the design of testing situations will be presented. [less ▲]

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See detailOutlier identification of differential item functioning in multiple groups
Magis, David ULg; De Boeck, Paul

Conference (2010, July)

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2009) proposed to identify differentially functioning items as outliers in a one ... [more ▼]

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2009) proposed to identify differentially functioning items as outliers in a one-dimensional space of DIF measures, using robust statistical tools for outlier identification. The purpose of this talk is to present an extension of this approach for the case of more than one focal group. In this multiple group framework, items can be characterized by multiple vectors of DIF measures, one for each focal group, so that a multivariate DIF space is obtained. DIF items can then be identified as outliers in this multivariate space, based on robust multivariate estimators of location and dispersion. The MCD (Minimum Covariance Determinant) estimator is shown to be adequate for this purpose. A major asset of the method that it can rely on existing DIF indices to define the DIF vectors, and that it does not need a purification step. Alternatively, it can be used to determine on an anchor set. The method will be illustrated by an example about calculator effects on mathematics test items. [less ▲]

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See detailDetection of differential item functioning with the difR package
Magis, David ULg; Béland, Sébastien; Tuerlinckx, Francis et al

Poster (2010, July)

The purpose of this talk is to briefly present the package difR of the software R. This package permits to identify differential item functioning (DIF) with several parametric or nonparametric methods ... [more ▼]

The purpose of this talk is to briefly present the package difR of the software R. This package permits to identify differential item functioning (DIF) with several parametric or nonparametric methods. Nonparametric methods include: Mantel-Haenszel, standardization, logistic regression and Breslow-Day. Available parametric methods are the Lord’s chi-square test, the Raju’s area method, and the likelihood-ratio test. Some methods for DIF identification in multiple groups (generalized Mantel-Haenszel, generalized Lord’s test) are also available. The presentation focuses on the package and its potential, rather than on the included methods. Its performance will be illustrated with an example data set. [less ▲]

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See detailUsing Snijders’ approach to standardize some parametric person fit indexes with estimated ability levels: a simulation study
Béland, Sébastien; Magis, David ULg; Raîche, Gilles

Conference (2010, July)

Several authors (Molenaar & Hoijtink, 1990; Meijer & Sijtsma, 2001) have shown that several person-fit statistics present some important limitations. One issue is that the distribution of some parametric ... [more ▼]

Several authors (Molenaar & Hoijtink, 1990; Meijer & Sijtsma, 2001) have shown that several person-fit statistics present some important limitations. One issue is that the distribution of some parametric person-fit statistics is unknown. Another important issue is that the distribution of person-fit indexes is most often derived under the true ability level. In this situation, replacing the true ability by some estimate can seriously affect the distribution of these indexes. Snijders (2001) proposed a method to correct the mean and the variance of many parametric person-fit statistics to be approximately standard normally distributed, and derived the corrected version of the lz index. The purpose of this paper is to apply this correction to other well-known parametric indexes, and to compare them with their classical versions. The simulation results indicate that the standardized indexes have empirical type I errors close to the nominal significance level, and that the corrected indexes outperform their classical versions in this regard. [less ▲]

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See detailDifferential item functioning among multiple groups: an outlier identification approach
Magis, David ULg

Scientific conference (2010, June 07)

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2010) proposed to identify differentially functioning items as outliers in a one ... [more ▼]

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2010) proposed to identify differentially functioning items as outliers in a one-dimensional space of DIF measures, using robust statistical tools for outlier identification. The purpose of this talk is to present an extension of this approach for the case of more than one focal group. In this multiple group framework, items can be characterized by multiple vectors of DIF measures, one for each focal group, so that a multivariate DIF space is obtained. DIF items can then be identified as outliers in this multivariate space, based on robust multivariate estimators of location and dispersion. The MCD (Minimum Covariance Determinant) estimator is shown to be adequate for this purpose. A major asset of the method that it can rely on existing DIF indices to define the DIF vectors, and that it does not need a purification step. Alternatively, it can be used to determine on an anchor set. The method will be illustrated by an example about calculator effects on mathematics test items. [less ▲]

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See detailLa théorie de la réponse aux items et le logiciel R
Béland, Sébastien; Raîche, Gilles; Magis, David ULg et al

Conference (2010, June)

Detailed reference viewed: 68 (4 ULg)
See detailDo Raven’s Colored Progressive Matrices function the same way in typical and clinical populations?
Nuchadee, Marie-Laure; Facon, Bruno; Magis, David ULg et al

Conference (2010, June)

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See detailComparaison des méthodes de Lord et de la régression logistique pour la détection du fonctionnement différentiel des items
Raîche, Gilles; Magis, David ULg; Béland, Sébastien

Conference (2010, May)

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See detailThree person-fit indexes with estimated ability level: a simulation study
Béland, Sébastien; Magis, David ULg; Raîche, Gilles et al

Conference (2010, April)

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See detailL’utilisation des simulations informatisées pour la recherche en éducation
Raîche, Gilles; Sodoké, Komi; Blais, Jean-Guy et al

in Potvin, Patrice; Vazquez-Abad, Jesus; Riopel, Martin (Eds.) Utilisation des technologies pour la recherche en éducation scientifique (2010)

Les méthodes de recherche en éducation se sont beaucoup développées au cours des dernières années. Pour les soutenir, des outils informatiques permettent d’automatiser diverses tâches répétitives et ... [more ▼]

Les méthodes de recherche en éducation se sont beaucoup développées au cours des dernières années. Pour les soutenir, des outils informatiques permettent d’automatiser diverses tâches répétitives et fastidieuses, ainsi que d’accélérer leur vitesse d’exécution. La capacité de réaliser la simulation, par méthodes stochastiques ou non stochastiques, de phénomènes impossibles à imaginer auparavant est une de ces tâches. Dans ce chapitre, nous définirons la notion de simulation en contexte de recherche, présenterons des principes et des méthodologies spécifiques de la mise en oeuvre d’une simulation, et nous illustrerons ces principes et méthodologies à partir de quelques exemples tirés de nos travaux de recherche. [less ▲]

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See detailAn iterative maximum a posteriori estimation of proficiency level to detect multiple local likelihood maxima
Magis, David ULg; Raîche, Gilles

in Applied Psychological Measurement (2010), 34

In this article the authors focus on the issue of the nonuniqueness of the maximum likelihood (ML) estimator of proficiency level in item response theory (with special attention to logistic models). The ... [more ▼]

In this article the authors focus on the issue of the nonuniqueness of the maximum likelihood (ML) estimator of proficiency level in item response theory (with special attention to logistic models). The usual maximum a posteriori (MAP) method offers a good alternative within that framework; however, this article highlights some drawbacks of its use. The authors then propose an iteratively based MAP estimator (IMAP), which can be useful in detecting multiple local likelihood maxima. The efficiency of the IMAP estimator is studied and is compared to the ML and MAP methods by means of a simulation study. [less ▲]

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See detailRIM: A random item mixture model to detect differential item functioning.
Frederickx, Sofie; Tuerlinckx, Francis; De Boeck, Paul et al

in Journal of Educational Measurement (2010), 47(4), 432-457

In this article we present a new methodology for detecting Di erential Item Functioning (DIF). We introduce a DIF model, called the Random Item Mixture (RIM), that is based on a Rasch model with random ... [more ▼]

In this article we present a new methodology for detecting Di erential Item Functioning (DIF). We introduce a DIF model, called the Random Item Mixture (RIM), that is based on a Rasch model with random item difficulties (besides the common random person abilities). In addition, a mixture model is assumed for the item difficulties such that the items may belong to one of two classes: a DIF or a non-DIF class. The crucial di fference between the DIF class and the non-DIF class is that the item difficulties in the DIF class may di ffer according to the observed person groups while they are equal across the person groups for the items from the non-DIF class. Statistical inference for the RIM is carried out in a Bayesian framework. The performance of the RIM is evaluated using a simulation study in which it is compared with traditional procedures, like the Likelihood Ratio test, the Mantel-Haenszel procedure and the standardized p-DIF procedure. In this comparison, the RIM performs better than the other methods. Finally, the usefulness of the model is also demonstrated on a real life dataset. [less ▲]

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See detailA general framework and an R package for the detection of dichotomous differential item functioning
Magis, David ULg; Béland, Sébastien; Tuerlinckx, Francis et al

in Behavior Research Methods (2010), 42

Differential item functioning (DIF) is an important issue of interest in psychometrics and educational measurement. Several methods have been proposed in the last decades to identify items that function ... [more ▼]

Differential item functioning (DIF) is an important issue of interest in psychometrics and educational measurement. Several methods have been proposed in the last decades to identify items that function differently between two (or more) groups of examinees. Starting from a framework for classifying DIF detection methods and from a comparative overview of the most traditional methods, an R package for nine methods, called difR, is presented. The commands and options are briefly described, and the package is illustrated through the analysis of a data set on verbal aggression. [less ▲]

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See detaildichoDIF: un package du logiciel R pour la détection du fonctionnement différentiel d'items dichotomiques en psychométrie
Magis, David ULg; Béland, Sébastien; Tuerlinckx, Francis et al

Conference (2009, November)

Detailed reference viewed: 14 (1 ULg)