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A Psychometric Analysis of a Three-Dimensional Spatial Task IRT

Bejar, Isaac I.
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Office of Naval Research, Cognitive Processes, Computer Assisted Testing, Item Response Theory (IRT), Psychometrics, Spatial Ability, Test Theory


The feasibility of incorporating research results from cognitive science into the modeling of performance on psychometric tests and the construction of test items is considered. Emphasis is on the feasibility of modeling performance on a three-dimensional rotation task within the context of Item Response Theory (IRT). Three-dimensional items were chosen because there is a rich literature on the mental models that are used in their solution. To test the feasibility of psychometrically modeling performance on this item type, an 80-item three-dimensional rotation test was constructed. An inexpensive computer system was also developed to administer the test and record performance, including response-time data. Information was gathered on high school juniors and seniors. As expected, angular disparity was a strong determinant of item difficulty. The applicability of IRT to these data was investigated by dichotomizing response time at several points and applying standard item parameter estimation procedures. An approach to psychometric modeling that explicitly incorporates information on the mental models examiners use in solving an item is not only workable, but also necessary for future developments in psychometrics. (SGK) (57pp.)

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