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.
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Research reported in this paper has been supported by grant GB-32781X from National Science Foundation.
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Lord, F.M. The relative efficiency of two tests as a function of ability level. Psychometrika 39, 351–358 (1974). https://doi.org/10.1007/BF02291708
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DOI: https://doi.org/10.1007/BF02291708