plotAdjacent: Plot category probabilities of adjacent category logit model
In netique/ShinyItemAnalysis: Test and Item Analysis via Shiny

Description Usage Arguments Value Author(s) See Also Examples

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

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

`x`	object of class `vglm`
`matching.name`	character: name of matching criterion used for estimation in `x`.

An object of class ggplot and/or gg.

Tomas Jurica
Institute of Computer Science of the Czech Academy of Sciences

Adela Hladka
Institute of Computer Science of the Czech Academy of Sciences
hladka@cs.cas.cz

Patricia Martinkova
Institute of Computer Science of the Czech Academy of Sciences
martinkova@cs.cas.cz

vglm

# 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")