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The Relative Efficiency of Two Tests as a Function of Ability Level

Published online by Cambridge University Press:  01 January 2025

Frederic M. Lord
Frederic M. Lord*
Affiliation:
Educational Testing Service, Princeton, N. J.
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Abstract

A new formula is developed for the relative efficiency of two tests measuring the same trait. The formula expresses relative efficiency solely in terms of the standard errors of measurement and, surprisingly, the frequency distributions of true scores. Approximate methods for estimating relative efficiency may make this function routinely available. A numerical illustration compares new and old estimates of relative efficiency for subtests from the Scholastic Aptitude Test.

Type
Original Paper
Information
Psychometrika , Volume 39 , Issue 3 , September 1974 , pp. 351 - 358
Copyright
Copyright © 1974 The Psychometric Society

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Footnotes

*

Research reported in this paper has been supported by grant GB-32781X from National Science Foundation.

References

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