A Note on "Efficiency of Multiple-Choice Tests as a Function of Spread of Item Difficulties" by Lee J. Cronbach (Psychometrika,1952, 17, 127-147)
- Author(s):
- Lord, Frederic M.
- Publication Year:
- 1953
- Report Number:
- RM-53-02
- Source:
- ETS Research Memorandum
- Document Type:
- Report
- Page Count:
- 4
- Subject/Key Words:
- Constructed Responses, Cronbach, Lee J., Difficulty Level, Equations (Mathematics), Free Response, Item Analysis, Multiple Choice Tests, Test Items, Test Reliability
Abstract
A table enlarging Cronbach's Table 1 is presented here to translate Cronbach's delta into some more familiar measure of item discriminating power. It is assumed that all items are free-response items of 50-percent difficulty. An appendix gives the relations among the statistics in the table, according to the assumptions in Cronbach's article for the case where the items are free-response items with different percentages of correct answers and tetrachoric intercorrelations.
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