| CalculatePcmExp {DFIT} | R Documentation |
Calculates the expected item score under the (G)PCM model.
Description
Calculates the expected item score under the (G)PCM model.
Usage
CalculatePcmExp(thetaValue, itemParameters, logistic = TRUE)
Arguments
thetaValue |
A numeric value or array for the theta (ability) value(s) where the difference will be calculated |
itemParameters |
A matrix containing the numeric values of item discriminations on the first column and category thresholds on the rest columns where the (column position - 1) indicates the category score or weight. |
logistic |
A logical value stating if the IRT model will use the logistic or the normal metric. |
Value
expectedScore A numeric matrix with the expected score on each thetaValue for each item.
Author(s)
Victor H. Cervantes <vhcervantesb at unal.edu.co>
References
de Ayala, R. J., (2009). The theory and practice of item response theory. New York: The Guildford Press
Oshima, T. & Morris, S. (2008). Raju's Differential Functioning of Items and Tests (DFIT). Educational Measurement: Issues and Practice, 27(3), 43–50. doi:10.1111/j.1745-3992.2008.00127.x