psychotools (version 0.7-4)

rrsm: Simulate Data under a Rating Scale Model

Description

rrsm simulates IRT data under a rating scale model.

Usage

rrsm(theta, beta, tau, nullcats = FALSE, return_setting = TRUE)

Value

rrsm returns either a list of the following components:

beta

numeric vector of item difficulty parameters used,

tau

numeric vector of threshold parameters used,

theta

numeric vector (or list) of person parameters used,

data

numeric matrix containing the simulated data,

or (if return_setting = FALSE) only the numeric matrix containing the simulated data.

Arguments

theta

numeric vector of person parameters. Can also be a list, then a list of length length(theta) is returned, containing multiple simulated data sets.

beta

numeric vector of item difficulty parameters.

tau

numeric vector of threshold parameters.

nullcats

logical. Should null categories be allowed?

return_setting

logical. Should a list containing slots of "beta", "tau", and "theta", as well as the simulated data matrix "data" be returned (default) or only the simulated data matrix?

See Also

rpcm, rgpcm, rrm, rpl

Examples

set.seed(1)
## item responses under a rating scale model (RSM) with
## 6 persons with three different person parameters
## 9 increasingly difficult items
## 3 different threshold parameters
ppar <- rep(-1:1, each = 2)
ipar <- seq(-2, 2, by = 0.5)
tpar <- 0:2
sim <- rrsm(theta = ppar, beta = ipar, tau = tpar)

## simulated item response data along with setting parameters
sim

## print and plot corresponding item response object
iresp <- itemresp(sim$data)
iresp
plot(iresp)