mirt (version 1.33.2)

read.mirt: Translate mirt parameters into suitable structure for plink package

Description

This function exports item parameters from the mirt package to the plink package.

Usage

read.mirt(x, as.irt.pars = TRUE, ...)

Arguments

x

an object returned from mirt, bfactor, or multipleGroup

as.irt.pars

if TRUE, the parameters will be output as an irt.pars object

...

additional arguments to be passed to coef()

Examples

Run this code
# NOT RUN {
# }
# NOT RUN {
## unidimensional
library(plink)

data <- expand.table(LSAT7)
(mod1 <- mirt(data, 1))
plinkpars <- read.mirt(mod1)
plot(plinkpars)
plot(mod1, type = 'trace')

#graded
mod2 <- mirt(Science, 1)
plinkpars <- read.mirt(mod2)
plot(plinkpars)
plot(mod2, type = 'trace')

#gpcm
mod3 <- mirt(Science, 1, itemtype = 'gpcm')
plinkpars <- read.mirt(mod3)
plot(plinkpars)
plot(mod3, type = 'trace')

#nominal
mod4 <- mirt(Science, 1, itemtype = 'nominal')
plinkpars <- read.mirt(mod4)
plot(plinkpars)
plot(mod4, type = 'trace')

## multidimensional

data <- expand.table(LSAT7)
(mod1 <- mirt(data, 2))
plinkpars <- read.mirt(mod1)
plinkpars
plot(plinkpars)
plot(mod1, type = 'trace')

cmod <- mirt.model('
   F1 = 1,4,5
   F2 = 2-4')
model <- mirt(data, cmod)
plot(read.mirt(model))
itemplot(model, 1)

#graded
mod2 <- mirt(Science, 2)
plinkpars <- read.mirt(mod2)
plinkpars
plot(plinkpars)
plot(mod2, type = 'trace')

### multiple group equating example
set.seed(1234)
dat <- expand.table(LSAT7)
group <- sample(c('g1', 'g2'), nrow(dat), TRUE)
mod <- multipleGroup(dat, 1, group)

# convert, and combine pars
plinkMG <- read.mirt(mod)
combine <- matrix(1:5, 5, 2)
comb <- combine.pars(plinkMG, combine, grp.names=unique(group))
out <- plink(comb, rescale="SL")
equate(out)
equate(out, method = 'OSE')

# }

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