plotICC {eatModel} | R Documentation |
Function provides item characteristic plots for each item. To date, only dichotomouls 1pl and 2pl models are supported.
plotICC ( resultsObj, defineModelObj, item = NULL, personsPerGroup = 30, pdfFolder = NULL, smooth = 20 )
resultsObj |
The object returned by |
defineModelObj |
The object returned by |
item |
Optional: The item for which the ICC should be plotted. If NULL, ICCs of all items
will be collected in a common pdf. The |
personsPerGroup |
Specifies the number of persons in each interval of the theta scale for dividing the persons in various groups according to mean EAP score. |
pdfFolder |
Optional: A folder with writing access for the pdf file. Necessary only if ICCs for more than one item should be plotted. |
smooth |
Optional: A parameter (integer vaklue) for smoothing the plot. If the number of examinees is high, the
icc plot may become scratchy. |
This function is beta! Use with care...
Sebastian Weirich
data(sciences) # first reshape the data set into wide format datW <- reshape2::dcast(sciences, id+grade+sex~variable, value.var="value") # defining the model: specifying q matrix is not necessary mod1 <- defineModel(dat=datW, items= -c(1:3), id="id", software = "tam") # run the model run1 <- runModel(mod1) # get the results res1 <- getResults(run1) # plot for one item plotICC ( resultsObj = res1, defineModelObj = mod1, item = "BioPro13")