sim_style_data: Simulate Data From a Multidimensional Rasch Model

Description Usage Arguments Value References

View source: R/fun_simulate-data.R

Description

This function allows to simulate data from a multidimensional Rasch model, in which one (or more) latent variables represent response styles such as extreme response style or acquiescence.

Usage

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sim_style_data(n = 200, items = 10, categ = 5, ndimc = 1,
  style = NULL, irtmodel = "RSM", reversed = 1/3, var.s, mu.s = 0,
  cor.cc, pop.thres = FALSE, my.theta, my.thres, emp = TRUE, sig = NULL)

Arguments

n

Numeric. Desired number of observations/persons.

items

Numeric. Desired number of items/stimuli. If ndimc > 1, this specifies the number of items per dimension.

categ

Numeric. Desired number of categories per item.

ndimc

Numeric. Desired number of content-related latent variables (irrespective of number of style-related latent variables).

style

Parameter to specify which response style(s) influence the data, can be either numeric or character. Users may choose one or more among "ERS1" (e.g., 1 / 0 / 0 / 0 / 1), "ERS2" (e.g., 2 / 1 / 0 / 1 / 2), "ARS" (e.g., 0 / 0 / 0 / 1 / 1), "ADRS" (e.g, -1 / -1 / 0 / 1 / 1), and "MRS" (e.g., 0 / 0 / 1 / 0 / 0). Alternatively, a user-specified vector of weights can be employed. Can also be NULL indicating complete abscence of response styles.

irtmodel

A character string indicating which model to use. Currently available is "RSM" (i.e., rating scale model).

reversed

Numeric. Indicates the number of reverse-coded items. Can be either a ratio between 0 and 1 indicating the ratio of reverse-coded items or an integer between 0 and items) indicating the number of reverse-coded items.

var.s

Numeric. The variance(s) of the response style distribution.

mu.s

Numeric. The mean(s) of the response style distribution.

cor.cc

An optional vector indicating the correlation between the content-related variables (if ndimc > 1). If ndimc > 2, cor.cc is recycled if it is not of length ndimc*(ndimc-1)/2.

pop.thres

Logical. If TRUE, the thresholds of the RSM are set to their expected value.

my.theta

Optional argument to employ a pre-specified vector of person parameters theta

my.thres

Optional argument to employ a pre-specified vector of item parameters.

emp

Logical. If true, mu.s and var.s/sig specify the empirical not population mean and covariance matrix.

sig

Numeric matrix. The variance-covariance matrix of the multivariate distribution of thetas. If non-NULL, this overrides var.s.

Value

Returns a list containing the data and basically a summary of the input specifications:

dat

An array containing the data/responses of format n x items x ndimc

theta

A matrix containing the true person parameters of format n x (ndimc + length(style)). For example, if ndimc = 1, and style = c("ERS1", "ARS"), then the second column corresponds to "ERS1" and the third column to "ARS".

item.par

A vector of item parameters

n

n

items.per.dim

Number of items per dimension

rev.coded.items

Number of reverse-coded items per dimension

categories

categ

irtmodel

irtmodel

dims.content

ndimc

var.style

Variance of the style-related latent variable(s).

c.c.cor

Correlation of the content-related latent variables.

response.style

style – The specified response style(s)

coding – The implied coding scheme

mumu.s

sig – The employed variance-covariance matrix

References

Adams, R. J., Wilson, M., & Wang, W.-C. (1997). The multidimensional random coefficients multinomial logit model. Applied Psychological Measurement, 21, 1-23. doi:10.1177/0146621697211001

Plieninger, H. (in press). Mountain or molehill: A simulation study on the impact of reponse styles. Educational and Psychological Measurement.

Wetzel, E. & Carstensen, C. H. (2015). Multidimensional modeling of traits and response styles. European Journal of Psychological Assessment. Advance online publication. doi:10.1027/1015-5759/a000291


hplieninger/stylesim documentation built on May 17, 2019, 4:54 p.m.