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visualize IRCCC from mirt or ltm object.

gg_irccc.Rd

gg_irccc visualize IRCCC from mirt or ltm object.

Usage

gg_irccc(
  object,
  item,
  theta = c(-3, 3),
  breaks = 100,
  grm = TRUE,
  monochrome = FALSE,
  use_ltm = FALSE,
  output.data = FALSE
)

Arguments

object

mirt or grm object. If you use the grm object, you must set ltm = TRUE.

item

numeric. The number of the item to be visualized. The length must be 1.

theta

vector. The length must be 2. Specify the range of theta in the IRCCC to be visualized using c().

breaks

numeric. Specifies the number of divisions of theta. For example, if you specify 1000, the range specified by theta will be divided into 1000 parts. The default is 100.

grm

logical. The default is TRUE. If the object is GRM, set it to TRUE, and if it is a binary type, set it to FALSE.

monochrome

logical. The default is FALSE, and IRCCC is output in color. If TRUE, IRCCC is output in black and white.

use_ltm

logical. The default is FALSE. If you are using the mirt object, set this to FALSE. If you are using the grm object from the ltm package, set this option to TRUE. When use_ltm = TRUE, the scale factor D is corrected to 1.701.

output.data

logical. The default is FALSE. If TRUE, instead of visualizing IRCCC, the data that forms the basis of IRCCC is output in long format.

Value

Visualize the IRCCC of the specified item from the mirt or ltm object (output.data = FALSE). Output data that can visualize the IRCCC of the specified item from the mirt or ltm object (output.data = TRUE).

Examples

#library(mirt)
#data(Bock1997)
#dat <- Bock1997[1:3]
#res <- mirt(dat, model = 1, itemtype = "graded")

#gg_irccc(object = res, item = 1)
#plot1 <- gg_irccc(object = res, item = 1)
#plot1 + theme_bw()

#library(ltm)
#res <- grm(dat[1:3], IRT.param = TRUE)

#gg_irccc(object = res, item = 1, use_ltm = TRUE)
#d <- gg_irccc(object = res, item = 1, output.data = TRUE)