dgp_multi: Data generating process for multidimensional Rasch models

In lucasmanuelkohler/anchorpoint: Anchor Point Selection Based on the Gini Inequality Criterion

Description

Data generating process for multidimensional Rasch models (only two dimensions are supported at the moment)

Usage

dgp_multi(
  nobs,
  tlength,
  DIFpercent,
  Nr.dim = 2,
  Theta = NULL,
  discriminations = NULL,
  difficulties = NULL,
  DIF_mode = "intersect",
  d_distr = list(mean = 0, sd = 0.2),
  MultiNorm = NULL,
  itemtype = "dich"
)

Arguments

nobs	positive integer, number of total observations (default 1000) or positive integer vector vector of length 2, number of observations per group
tlength	interger > 0, test length (number of items)
DIFpercent	percentage of DIF items in the test
Nr.dim	positive integer, number of dimensions (default 2)
Theta	matrix of the underlying ability parameters (optional)
discriminations	binary matrix of size tlength x Nr.dim, item discrimination parameter matrix
difficulties	numeric vector of length tlength, item difficulty vector
DIF_mode	string, mode how DIF items are created, default: intersect.
d_distr	d_distr: parameters for normal distribution to generate item difficulties difficulties, default: mean = 0, sd = .2
MultiNorm	list with parameters for multivariate normal distribution to generate the abilities of the test takers in group 1 and group 2, respectively.
itemtype	type of items (default "dich" which corresponds to multidimensional Rasch model items)

Value

list consisting of:

• dat: binary response matrix

• groups: group vector (factor),

• discriminations: binary matrix containing the item discrimination parameter matrix,

• difficulties: item difficulty vector,

• DIFindex: indicating which items were generated with DIF,

• Theta,

• DIFside: which group is favored, default focal group is favored

References

Credit: Data is generated using the function simdata from mirt (Version: 1.32.1):

• R. Philip Chalmers (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29.

Examples

# For examples, see ?getData.

lucasmanuelkohler/anchorpoint documentation built on April 16, 2021, 6:41 a.m.