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Maximum Likelihood Estimation of Item Response Parameters When Some Responses Are Omitted

Lord, Frederic M.
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Office of Naval Research, Guessing Tests, Item Response Theory, Mathematical Models, Maximum Likelihood Statistics, Omitted Responses, Responses, Scoring, Testing Problems


Explored are two theoretical approaches that attempt to cope with omitted responses, that is, when an examinee omits (fails to respond to) an item and therefore the item response formula cannot be used. Preliminary considerations are discussed, and it is shown that a conveniently simple application of equivalent items leads to internal contradictions. A rigorous mathematical model for response or omission is suggested as a plausible alternative. Special cases of the model are investigated for insight into implementation of the model, but are not recommended for practical use. (Author/PN). (23pp.)

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