The area between two item characteristic curves


Formulas for computing the exact signed and unsigned areas between two item characteristic curves (ICCs) are presented. It is further shown that when thec parameters are unequal, the area between two ICCs is infinite. The significance of the exact area measures for item bias research is discussed.

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Correspondence to Nambury S. Raju.

Additional information

The author expresses his appreciation to Jeffrey A. Slinde, Stephen Steinhaus, Audrey Qualls-Payne, Ivo Molenaar, and two anonymous reviewers for their very helpful and constructive comments.

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Raju, N.S. The area between two item characteristic curves. Psychometrika 53, 495–502 (1988).

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Key words

  • item response theory
  • item bias
  • item characteristic curves