CalculateGrmExp: Calculates the expected item score under the GRM model.
In DFIT: Differential Functioning of Items and Tests

Description Usage Arguments Value Author(s) References

Calculates the expected item score under the GRM model.

1	CalculateGrmExp(thetaValue, itemParameters, logistic = TRUE)

`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.

expectedScore A numeric matrix with the expected score on each thetaValue for each item.

Victor H. Cervantes <vhcervantesb at unal.edu.co>

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

DFIT documentation built on Aug. 17, 2021, 9:07 a.m.