plotAdjacent: Plot category probabilities of adjacent category logit model

In ShinyItemAnalysis: Test and Item Analysis via Shiny

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.

Author(s)

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

Adela Hladka
Institute of Computer Science of the Czech Academy of Sciences
[e-mail]

Patricia Martinkova
Institute of Computer Science of the Czech Academy of Sciences
[e-mail]

See Also

VGAM::vglm()

Examples

# 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")

ShinyItemAnalysis documentation built on May 31, 2023, 7:08 p.m.