psketto: Plot a Single ICC

Description Usage Arguments Value Examples

View source: R/psketto.R

Description

psketto is singlular of psketti; (spaghetti <–> spaghetto). This function plots the data for a single item from the output of 'pskettify()'. 'psketto()' is also used in 'psketti()' to create multiple ICC plots. Based on Asril and Marais (2011).

Usage

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psketto(
  pskettified_data,
  item,
  item.label,
  style = "present",
  IRFLocation = TRUE,
  empCI = TRUE,
  empICC = TRUE,
  empPoints = TRUE,
  facet_curves = FALSE
)

Arguments

pskettified_data

input data, generated using 'pskettify()'.

item

character name of the item to be plotted

item.label

a character string of the item name to use.

style

a character string for plotting style options are present for coloured, or print for black and white. Defaults to "present".

IRFLocation

logical, plots reference lines for Rasch IRF location. Defaults to 'TRUE'

empCI

logical, plots confidence intervals for empirical points, calculated using 'pskettify()'. Defaults to 'TRUE'

empICC

logical, plots empirical ICC for item. Defaults to 'TRUE'

empPoints

logical, plots empirical points for based on class intervals/score groups generated with 'pskettify()'. Defaults to 'TRUE'

facet_curves

logical, should the plot be faceted by category curve? Applies only to polytomous Rasch models. Defaults to 'FALSE',.

Value

psketto plot.

Examples

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library(eRm)
library(psketti)

data("FakeData") # load data
# restructure fake data
Fake_Data_scores <- reshape(FakeData[, c("ID", "Item", "X")],
                            timevar = "Item",
                            idvar = "ID",
                            direction = "wide")
# for eRm col names and row names
names(Fake_Data_scores) <- c("ID",
                             paste0("i",
                                    sprintf(fmt  = "%02d", 1:23)))
                                    
row.names(Fake_Data_scores) <- Fake_Data_scores$ID
Fake_Data_scores$ID         <- NULL

fake_rm   <- RM(Fake_Data_scores) # Estimate Rasch model

psk_data  <- pskettify(fake_rm)   # pskettify data

# plot IRF in default colours
psk_1_present <- psketto(psk_data,
                         style = "present",
                         item = "i01",
                         item.label = "i01")
psk_1_present # plot output

# plot IRF in default greyscale colours
psk_1_print <- psketto(psk_data,
                       style = "print",
                       item = "i01",
                       item.label = "i01")
psk_1_print # plot output

SBGalvin/psketti documentation built on March 13, 2021, 1:47 p.m.