jacobian_irtree: Check identifiability of models.

Description Usage Arguments Examples

View source: R/jacobian.R

Description

Generate random parameter values and test, whether the Jacobian has full rank.

Usage

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jacobian_irtree(N, J, revItem = rep(1, J), traitItem = rep(1, J), type,
  fixed.theta = TRUE, rep = 100, betas, theta)

Arguments

N

number of persons

J

number of items

revItem

vector of length J specifying reversed items (1=reversed, 0=regular)

traitItem

vector of length J specifying the underlying traits (e.g., indexed from 1...5). Standard: only a single trait is measured by all items. If the Big5 are measured, might be something like c(1,1,1,2,2,2,...,5,5,5,5)

type

either "2012", "ext", "ext2", or "ext3"

fixed.theta

if TRUE, assumes that mean of theta parameters is assumed to be fixed at zero

rep

number of points in parameter space to check identification

betas

optional matrix with beta parameters

theta

optional matrix with theta parameters (note that the parameters of the first person will be set to to minus the theta-column means if fixed.theta=TRUE)

Examples

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# Standard model identified, even without reversed items:
jacobian_irtree(N=6, J=8, revItem=rep(1,8), type=2012, rep=5)

hplieninger/mpt2irt documentation built on Aug. 4, 2018, 10:52 a.m.