ShinyItemAnalysis (version 1.3.6)

plotAdjacent: Plot category probabilities of adjacent category logit model

Description

Function for plotting category probabilities function estimated by vglm() function from the VGAM package using the ggplot2 package.

Usage

plotAdjacent(x, matching.name = "matching")

Arguments

x

object of class vglm

matching.name

character: name of matching criterion used for estimation in x.

Value

An object of class ggplot and/or gg.

See Also

vglm

Examples

# NOT RUN {
# loading packages
library(VGAM)

# loading data
data(Science, package = "mirt")

# total score calculation
score <- rowSums(Science)
Science[, 1] <- factor(Science[, 1], levels = sort(unique(Science[, 1])), ordered = TRUE)

# adjacent category logit model for item 1
fit <- vglm(Science[, 1] ~ score, family = acat(reverse = FALSE, parallel = TRUE))
# coefficients for item 1
coef(fit)

plotAdjacent(fit, matching.name = "Total score")
# }