Contribution of Verbal Item Types in the GRE General Test to Accuracy of Measurement of the Verbal Scores
- Lord, Frederic M.; Wild, Cheryl L.
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- Item response theory (IRT) test items test reliability test validity verbal tests
The main purpose of this study is to compare the contribution to measurement accuracy of the verbal score of each of the four verbal item types included in the GRE General Test. Comparisons are based on item response theory, a methodology that allows the researcher to look at the accuracy of individual points on the score scale. This methodology is based on the assumption that the four verbal item types measure the same verbal ability. Since the results of the study do indicate that the reading comprehension item type measures something slightly different from what is measured by sentence completion, analogy, or antonym item types, only tentative conclusions may be drawn. The antonym item type contributes the most accuracy of the four item types for scores above about 550. Analogy items contribute to the measurement accuracy of verbal ability throughout the score range. This is especially true when item types are matched on verbal difficulty. These results suggest that the analogy and antonym item types are useful for maintaining accuracy of the verbal score scale at the upper levels. Eliminating these items might have a serious impact on the validity of the GRE verbal score in the upper regions of the scale. Studies of the validity of item types at the upper score range using external criteria would be necessary to understand the exact contribution of the item types to the validity of the test.