itemplot

a computed model object of class
  <code>ExploratoryClass</code>, <code>ConfirmatoryClass</code>, or
  <code>MultipleGroupClass</code>. Input may also be a
  <code>list</code> for comparing similar item types (e.g., 1PL
  vs 2PL)

object

a single numeric value indicating which item
  to plot

item

plot type to use, information
  (<code>'info'</code>), item trace lines (<code>'trace'</code>),
  relative efficiency lines (<code>'RE'</code>), expected score
  <code>'score'</code>, or information contours
  <code>('infocontour')</code> (not for <code>M</code>

type

the degrees argument to be used if there
  are exactly two factors. See <code><a href="/link/iteminfo?package=mirt&version=0.4.2" rd-options="" data-mini-rdoc="mirt::iteminfo">iteminfo</a></code> for
  more detail

degrees

additional arguments to be passed to lattice

<code>itemplot</code> displays various item based IRT plots.

plot

Analysis of dichotomous and polytomous response data using
        latent trait models under the Item Response Theory paradigm.
        Includes univariate and multivariate one-, two-, three-, and
        four-parameter logistic models, graded response models, rating
        scale graded response models, generalized partial credit
        models, nominal models, multiple choice models, and
        multivariate partially-compensatory models. These can be used
        in an exploratory or confirmatory manner with optional user
        defined linear constraints. Exploratory models can be estimated
        via quadrature or stochastic methods, a generalized
        confirmatory bi-factor analysis is included, and confirmatory
        models can be fit with a Metropolis-Hastings Robbins-Monro
        algorithm which can include polynomial or product constructed
        latent traits. Additionally, multiple group analysis may be
        performed for unidimensional or multidimensional item response
        models for detecting differential item functioning.

itemplot: Displays item surface and information plots

Description

Usage

Arguments

Examples