ERIC Number: EJ922102
Record Type: Journal
Publication Date: 2004-Mar
Abstractor: As Provided
Reference Count: 18
Reliability as a Function of the Number of Item Options Derived from the "Knowledge or Random Guessing" Model
MacCann, Robert G.
Psychometrika, v69 n1 p147-157 Mar 2004
For (0, 1) scored multiple-choice tests, a formula giving test reliability as a function of the number of item options is derived, assuming the "knowledge or random guessing model," the parallelism of the new and old tests (apart from the guessing probability), and the assumptions of classical test theory. It is shown that the formula is a more general case of an equation by Lord, and reduces to Lord's equation if the items are effectively parallel. Further, the formula is shown to be closely related to another formula derived from Lord's randomly parallel tests model.
Descriptors: Guessing (Tests), Multiple Choice Tests, Test Reliability, Test Theory, Test Items, Scoring Formulas
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Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
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