Simultaneous multifactor DIF analysis and detection in Item Response Theory
Item Response Theory (IRT) is a psychometric theory widely used in educational assessment and cognitive psychology to analyse data emerged from answers given to items contained in exams, questionnaires, etc. Standard IRT, however, is based on models which assume that items behave equally to all individuals. This may not be a reasonable assumption, especially when the individuals taking the test have different social and/or cultural backgrounds. Differential Item Functioning (DIF) is an area of IRT which allows an item to be perceived differently by distinct groups, respecting its usual characteristics. DIF hypothesis avoids neglecting items that may behave differently among groups and may also be used to provide important information about differences in the populations involved in the study. In this paper, two integrated Bayesian models for DIF analysis in IRT are proposed and compared. Both models are based on a two component mixture with one component describing DIF and the other accounting for the absence of DIF. Another contribution of this paper is the approach of the simultaneous presence of multiple factors causing DIF. Ideas from ANOVA models are used to characterize different possibilities associated with these factors. The models are also extended to account for explanation and detection in each factor. A simulation study was conducted to assess the model’s capabilities and to compare it against existing alternatives. Special attention has been directed to the conditions required to ensure model identification. An analysis of a Mathematics exam applied nationally to Brazilian elementary school students is made considering two DIF factors: geographical region and type of school. The results highlight the relevance of the proposed methodology to address important issues in educational studying and testing.
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
When requesting a correction, please mention this item's handle: RePEc:eee:csdana:v:59:y:2013:i:c:p:144-160. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Zhang, Lei)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.