m Habibi; fatemeh moradi; balal Izanlo
Volume 2, Issue 6 , January 2012, , Pages 1-27
Abstract
Background: Discussion about invariance of questions and tests is an important issue in assessment.
Objectives: The present study was conducted to compare the invariance of the parameters in item-response theory and confirmatory factor analysis.
Methods: After reviewing the related basics of each approach, ...
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Background: Discussion about invariance of questions and tests is an important issue in assessment.
Objectives: The present study was conducted to compare the invariance of the parameters in item-response theory and confirmatory factor analysis.
Methods: After reviewing the related basics of each approach, the researcher compared the invariance of the parameters in each approach based on empirical data result from International Reading Literacy Study (PIRLS) Test. The sample was 5000 Iranian students (half female and half male) in 2006 who responded to six questions which were related to the scale of attitude toward reading.
Results: Data analysis showed that question 6 is biased using both item-response theory and confirmatory factor analysis. The results, however, were different considering questions 1, 3 and 4. Question 1 was found to be biased based on item-response theory only; questions 3 and 4, on the other hand, were found to be biased based on confirmatory factor analysis.
Conclusion: It is suggested that both approaches be employed when deciding on the invariance of the parameters, since making decisions otherwise will be misleading. Also, it is offered that intercept and differences in the distribution of the ability of the groups and their effects on the invariance be considered as primary.
