A Steps Model to Analyze Partial Credit

  • N. D. Verhelst
  • C. A. W. Glas
  • H. H. de Vries


The partial credit model (PCM) by Masters (1982, this volume) is a unidimensional item response model for analyzing responses scored in two or more ordered categories. The model has some very desirable properties: it is an exponential family, so minimal sufficient statistics for both the item and person parameters exist, and it allows conditional-maximum likelihood (CML) estimation. However, it will be shown that the relation between the response categories and the item parameters is rather complicated. As a consequence, the PCM may not always be the most appropriate model for analyzing data.


Item Parameter Step Model Partial Credit Discrimination Parameter Item Response Model 
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Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • N. D. Verhelst
  • C. A. W. Glas
  • H. H. de Vries

There are no affiliations available

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