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Conditional Covariance Theory and Detect for Polytomous Items
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Zhang, Jinming – Psychometrika, 2007
This paper extends the theory of conditional covariances to polytomous items. It has been proven that under some mild conditions, commonly assumed in the analysis of response data, the conditional covariance of two items, dichotomously or polytomously scored, given an appropriately chosen composite is positive if, and only if, the two items…
Descriptors: Grade 4, National Competency Tests, Test Items, Grade 8