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The Asymptotic Distribution of Average Test Overlap Rate in Computerized Adaptive Testing

Published online by Cambridge University Press:  01 January 2025

Edison M. Choe*
Affiliation:
Graduate Management Admission Council™ (GMAC™)
Hua-Hua Chang
Affiliation:
Purdue University
*
Correspondence should be made to Edison M. Choe, Graduate Management Admission Council™ (GMAC™), 11921 Freedom Drive, Suite 300, Reston, VA 20190, USA. Email: echoe@gmac.com

Abstract

The average test overlap rate is often computed and reported as a measure of test security risk or item pool utilization of a computerized adaptive test (CAT). Despite the prevalent use of this sample statistic in both literature and operations, its sampling distribution has never been known nor studied in earnest. In response, a proof is presented for the asymptotic distribution of a linear transformation of the average test overlap rate in fixed-length CAT. The theoretical results enable the estimation of standard error and construction of confidence intervals. Moreover, a practical simulation study demonstrates the statistical comparison of average test overlap rates between two CAT designs with different exposure control methods.

Information

Type
Original Paper
Copyright
Copyright © 2019 The Psychometric Society

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