'eRm' objectsCalculates and plots the individual item-category information (type='category'), item information (type='item') or test/scale information (i.e., summed item information, type='scale' or 'test') ) as defined by Samejima (1969)
plotINFO(ermobject, type = "both", theta = seq(-6, 6, length.out = 1001L),
legpos = "topright", ...)
An object of class 'eRm'.
A string denoting the type of information to be
plotted. Currently supports "category", "item",
"test", "scale" and "both" (which gives item
and scale information; default).
Supporting or sampling points on the latent trait.
Defines the positioning of the legend, as in plotICC.
Further arguments.
xlab sets the label of the \(x\) axis.
ylabI and ylabT control the labeling of the item or test information plot.
mainI and mainT set the titles for item/test information plots.
Thomas Rusch
Samejima, F. (1969) Estimation of latent ability using a response pattern of graded scores. Psychometric Monographs, 17.
The function to calculate the item or test information, item_info and test_info.
res <- PCM(pcmdat)
plotINFO(res)
Run the code above in your browser using DataLab