AseIrt: Calculates the asymptotic covariance matrices for item...

In DFIT: Differential Functioning of Items and Tests

Description

Calculates the asymptotic covariance matrices for item parameters according with the IRT model.

Usage

AseIrt(
  itemParameters,
  distribution = "norm",
  distributionParameters = list(mean = 0, sd = 1),
  logistic = TRUE,
  sampleSize = 1,
  irtModel = "3pl",
  subdivisions = 5000
)

Arguments

itemParameters	A matrix or vector containing the item difficulties.
distribution	A string character indicating the generic name for the assumed distribution. Defaults to 'norm' for normal distribution.
distributionParameters	A list of extra parameters for the distribution function.
logistic	A logical indicating whether the logistic or the normal metric should be used.
sampleSize	A value indicating the sample size.
irtModel	A string stating the IRT model for all items.
subdivisions	A numeric value stating the maximum number of subdivisions for adaptive quadrature.

Value

ase A list containing the asymptotic matrices for each item

Author(s)

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

References

Li, Y. & Lissitz, R. (2004). Applications of the analytically derived standard errors of Item Response Theory item parameter estimates. Journal of educational measurement, 41(2), 85–117. doi:10.1111/j.1745-3984.2004.tb01109.x

Examples

# # Not run
# #
# # 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), ]
# #
# # threePlAse <- list()
# # threePlAse[["focal"]]     <- AseIrt(itemParameters = threePlParameters[["focal"]],
# #                                     logistic = TRUE,
# #                                     sampleSize = 10000,
# #                                     irtModel = "3pl")
# # threePlAse[["reference"]] <- AseIrt(itemParameters = threePlParameters[["reference"]],
# #                                     logistic = TRUE,
# #                                     sampleSize = 15000,
# #                                     irtModel = "3pl")

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