Mohsen Yazdanfar; Manijeh Shehni Yailagh; Ali Reza Haji Yakhchali; Sirous Alipour Birigani
Abstract
Dimensionality analysis or specify the number of latent traits that affect the data from the implementation of a scale or test and the study of local independency and monotonicity assumptions is of the important presuppositions to apply a item response theory model on a set of data. In this research, ...
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Dimensionality analysis or specify the number of latent traits that affect the data from the implementation of a scale or test and the study of local independency and monotonicity assumptions is of the important presuppositions to apply a item response theory model on a set of data. In this research, after a brief explanation of the local dependency indices and its models, In order to modeling the structure of cognitive abilities based on the data obtained from the implementation of the scale of cognitive abilities on a sample of 1105 students from the 9th grade students of Ahwaz selected by proportional stratified random sampling, after examining the hypothesis local independency through local dependency indices, monotonicity hypothesis and estimation of parameters of two one-dimensional and two-dimensional models and their comparison, The dimensionality of cognitive abilities was determined. The results showed that the dependency model observed between the data is perfectly locally dependent and Comparison of fitness indices of one-dimensional and two-dimensional model of Samejima graded response model showed that the two-dimensional model has better fit to the data than the one-dimensional model. In the following, using the concept of dimensionality factor space, a kind of comparison between the two classical test theories (CTT) and multidimensional item response theory (MIRT) was created and a kind of convergence in the results was obtained. The results showed that the fitness indices of classical theory alone were not able to characterize the structure of cognitive abilities, and methods based on item response theory in this field can be solved. The results of dimensionality analysis showed that the structure of cognitive abilities was two-dimensional; the first dimension of non-social cognition and the second dimension of social cognition were named and it was observed that these results converge with the results in the field of neuroscience.
mohammad ahmadi deh qutbuddini; ebrahim khodai; Valiollah Farzad; ali moghadam zadeh; masoud kabiri
Abstract
The present study has been done with the purpose of investigating the dimensionality and differential item functioning of the testlet-based test of Iran's PIRLS 2011. In order to analyze the dimensionality, graded response and bi-factor item-response theory models were used with full-information maximum ...
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The present study has been done with the purpose of investigating the dimensionality and differential item functioning of the testlet-based test of Iran's PIRLS 2011. In order to analyze the dimensionality, graded response and bi-factor item-response theory models were used with full-information maximum likelihood estimation method and to analyze the differential item functioning multiple-group bi-factor model of Cai et al (2011) was applied. The results of the dimensionality investigation showed that the bi-factor model is better fitted to the data than the graded response model both in Iran's total sample and in boy and girl groups. The results of testlets effect variance showed that effects of second factors on Iranian students' performance in two testlet related to literal comprehension, has caused dimensionality in Iran's PIRLS testlets. The results showed that there was no significant difference in average students' performance of the boy and girl in general latent trait of reading comprehension, but the difference between the average reading proficiency of the boy and the girl in three literal and three informational testlet in favor of girls was significant. The result of differential items functioning based on the bifactor model showed that many items have an uniform and non-uniform differential item functioning, and boys in multiple-choice items and girls in constructed response items have better performances. In general, the results showed that in Iran's PIRLS 2011 testlets, the traits related to the two literal comprehension testlets were differently perceived between boy and girl students, and these two testlet had more local item dependence among girls than boys. Also, the results indicated a difference between the performance of Iranian boy and girl students in the mixed items format test of PIRLS.