versión On-line ISSN 1668-7027
LOZZIA, Gabriela Susana; GALIBERT, María Silvia; AGUERRI, María Ester y ATTORRESI, Horacio Félix. A possibility of integration cognitive theory and modern psychometric. Interdisciplinaria [online]. 2005, vol.22, n.1, pp. 5-27. ISSN 1668-7027.
One of the advantages of the Item Response Theory (IRT) compared to the Classical Test Theory is the possibility of building measurement instruments with properties independent to the subjects to be measured with them. Within IRT it is verified that the difficulty and discrimination item parameters remain invariant no matter which subject population is used. An item bank is a set of items which measure the same variable and whose parameters are calibrated, that is estimated, in a common scale. Whenever an item bank is available, administrations of adaptive tests become possible; this means the bank offers the possibility of choosing those items which assess each subject more accurately. Also, it allows designs of tests with pre-established characteristics according to the measurement objective. The application of the IRT is still incipient in Argentina and Differential Item Functioning (DIF) studies have not been known so far. The aim of this work is to show the development of a Bank of Verbal Reasoning Items according to the IRT. This theory, as well as its application to the elaboration of item banks, are here in presented. These items measure the ability to identify and discriminate relationships among words. Such ability is related to the ideative factor of the verbal comprehension, which is common to all tasks of deductive, serial and probabilistic reasoning, classification and problem solution. Therefore, it is one of the main factors to get the intellectual aptitude profile of students. Each item consists of a pair of basic words with some relationship existing between them and four alternative pairs of words. The instruction commands to choose the pair with the most similar relationship to the one existing between the words in the basic pair. The construction of this bank has involved an iterative process of invention-calibration of the items. In the invention stage, the items have been selected and improved through successive pilot trials. In the selection processes, some classical statistics procedures were considered such as the question evaluation index. The calibration stage has been developed in two main phases: the initial phase and the current one. In the initial phase the calibration was done with samples from different student populations. Although some of them had responded different item sets, the calibration was done in a simultaneous running of the program BILOG-MGTM in order to obtain the estimates in a common scale. The assumption of unidimensionality was checked through a scree plot implemented by MicroFACTTM. The current phase consists of adding new items to the bank until it has a substantial number of them. Before calibration, DIF analysis have been done in both phases. Taking into account the different subjects of the corresponding samples, it is necessary to manage the items together with a small group of already calibrated ones. These items serve as a link so that the parameter estimates of the new items result in the same scale as the one of the rest of the bank. Link items have been chosen with difficulty parameters representing different levels of ability and high discrimination parameters. DIF analysis have been based on the normal test of the difference between the difficulty parameters, which has been obtained from BILOG-MGTM. This software as well as XCALIBRETM have been used to calibrate the items by fitting the three-parameter logistic model. Stout's test of essential unidimensionality analysis has been done by using DIMTEST. After removing those items which present DIF or where the model does not fit, 93 items have been remained for the bank.
Palabras clave : Item bank; Adaptive tests; Differential item functioning; Three parameter logistic model; Item Response Theory; Relationship items.