What it’s about

The goal of jrt is to provide tools to use Item-Response Theory (IRT) models on judgment data, especially in the context of the Consensual Assessment Technique, as presented in Myszkowski (2021).

• Myszkowski, N. (2021). Development of the R library “jrt”: Automated item response theory procedures for judgment data and their application with the consensual assessment technique. Psychology of Aesthetics, Creativity, and the Arts, 15(3), 426-438. http://dx.doi.org/10.1037/aca0000287

Vignette

The vignette can be found at https://cran.r-project.org/web/packages/jrt/vignettes/my-vignette.html

Installation

You can install the released version of jrt from CRAN with:

install.packages("jrt")

Example use

• Load the library

library(jrt)

## Loading required package: directlabels

• Load example dataset

data <- jrt::ratings

• To automatically select models

fit <- jrt(data)

• To select models a priori

fit <- jrt(data, irt.model = "PCM")

• To plot all category curves

jcc.plot(fit)

• To plot one judge’s category curves

jcc.plot(fit, judge = 1)

• Graphical options

jcc.plot(fit, 
         judge = 1,
         overlay.reliability = T, 
         greyscale = T, 
         theme = "classic",
         font.family = "serif")

• To plot total information

info.plot(fit)

• To plot judge information

info.plot(fit, judge = 1)

• Other options for information plots

info.plot(fit, type = "Reliability",
          y.line = .70,
          y.limits = c(0,1),
          theta.span = 4,
          theme = "classic")