Introduction: The quality of an MCQ type test depends on the qualities of the constituent items, assessed in terms of item reliability, item difficulty value, item discriminating value, etc. However, the quality of a test involving reliability, validity, difficulty, discriminating values of the test, etc. requires new approaches. Need is felt to find difficulty and discriminating values of an item and test using entire data and to derive relationships amongst them including the relationship with test reliability to see the impact of item deletion. Methods: Using angular similarity approach, measures proposed for item difficulty and item discriminating value, difficulty and discriminating value of the test. Relationship derived between (i) difficulty value and discriminating value of item; (ii) difficulty value and discriminating value of a test (iii) test discriminating value and test reliability as per theoretical definition. Cronbach alpha was expressed using the sum of item difficulty values and test discriminating value. Results and Discussion: Each proposed measure ranges between 0 to 1. Discriminating value of test and item as the coefficient of variation satisfy desired properties and facilitates population estimations. The intersection of item difficulty and item discriminating curves provides a data-driven criterion for item deletion, the impact of which on test reliability may be checked. In addition, the proposed measures facilitate testing of the statistical hypothesis of departure of test reliability from unity, confidence interval of reliability, etc. Future problems suggested.
Satyendra, Chakrabartty Nath
"Improved Quality: Item and Test Parameters,"
Health Sciences: Vol. 1
, Article 7.
Available at: https://doi.org/10.15342/hs.2020.267
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