Description Usage Arguments Value Author(s) References Examples
Calculates Raju's Signed Area Measure index for an item with given item parameters of focal and reference groups.
1 2 3 4 5 6 | SignedArea(
itemParameters,
irtModel = "2pl",
subdivisions = 5000,
logistic = TRUE
)
|
itemParameters |
A list containing "focal" and "reference" item parameters. Item parameters are assumed to be on the same scale. Item parameters for each group should me a matrix with nrow equal to the number of items. |
irtModel |
A string stating the irtModel to be used. Should be one of "1pl", "2pl", "3pl", "grm" or "pcm". |
subdivisions |
A numeric value indicating the number of subdivisions for numerical integration. |
logistic |
A logical value stating if the IRT model will use the logistic or the normal metric. Defaults to using the logistic metric by fixing the D constant to 1. If FALSE the constant is set to 1.702 so that the normal metric is used. |
sam A numeric matrix with the Signed Area Measure values for all the item parameter in each set of itemParameterList
Victor H. Cervantes <vhcervantesb at unal.edu.co>
Cohen, A., Kim, S-H and Baker , F. (1993). Detection of differential item functioning in the Graded Response Moodel. Applied psychological measurement, 17(4), 335-350. doi:10.1177/014662169301700402
Raju, N. (1988). The area between two item characteristic cureves. Psychometricka, 53(4), 495–502. doi:10.1007/bf02294403
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | data(dichotomousItemParameters)
threePlParameters <- dichotomousItemParameters
isNot3Pl <- ((dichotomousItemParameters[['focal']][, 3] == 0) |
(dichotomousItemParameters[['reference']][, 3] == 0))
threePlParameters[['focal']] <- threePlParameters[['focal']][!isNot3Pl, ]
threePlParameters[['reference']] <- threePlParameters[['reference']][!isNot3Pl, ]
threePlParameters[['focal']][, 3] <- threePlParameters[['focal']][, 3] + 0.1
threePlParameters[['reference']][, 3] <- threePlParameters[['reference']][, 3] + 0.1
threePlParameters[['focal']][, 2] <- threePlParameters[['focal']][, 2] + 1.5
threePlParameters[['reference']][, 2] <- threePlParameters[['reference']][, 2] + 1.5
threePlParameters[['focal']] <- threePlParameters[['focal']][-c(12, 16, 28), ]
threePlParameters[['reference']] <- threePlParameters[['reference']][-c(12, 16, 28), ]
sam3pl <- SignedArea(itemParameters = threePlParameters, irtModel = "3pl",
subdivisions = 5000, logistic = TRUE)
|
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