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An Application of Item Response Theory in the Comparison of Four Conventional Item Discrimination Indices for Criterion‐Referenced Tests
Author(s) -
Shan Gregory A.,
Cliver Barbara A.
Publication year - 1987
Publication title -
journal of educational measurement
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.917
H-Index - 47
eISSN - 1745-3984
pISSN - 0022-0655
DOI - 10.1111/j.1745-3984.1987.tb00285.x
Subject(s) - item response theory , statistics , rank (graph theory) , statistic , mathematics , spearman's rank correlation coefficient , psychology , econometrics , psychometrics , combinatorics
Several recent papers have argued for the usefulness of item response theory (IRT) methods of assessing item discrimination power for criterion‐referenced tests (CRTs). Conventional methods continue to be used more widely, however, for reasons that include some practical constraints associated with the use of IRT methods. To provide users with information that may help them to decide on which conventional indices to employ in evaluating CRT items, Spearman rank‐order correlations were computed between IRT‐derived item information functions (llFs) and four conventional discrimination indices: the phi‐coefficient, the B‐index, phi/phi max, and the agreement statistic. The rank‐order correlations between the phi‐coefficient and the llFs were very high, with a median of .96. The remaining conventional indices, with the exception of phi‐over‐phi‐max, also correlated well with the IIF. Theoretical explanations for these relationships are offered.