plotDif function

plotDif

Creates a plot (ggplot2 object) of item parameter estimates common to two system files (e.g., a DIF analysis).

plotDif(mySysToItemDifDf, myScale = "centred", mySuffixes)

Arguments

• mySysToItemDifDf: An R object of class data frame returned from conquestr::sysToItemDifDf
• myScale: A string specifying if the item parameter estimates displayed should be "centred" (default), "scaled" (z scores), or "none" (raw).
• mySuffixes: a vector of strings specifying the names for the two groups being analysed, e.g., if the two system files are an analysis of boys and girls, the vector may be c(_male", "_female").

Returns

A ggplot2 object.

Examples

mySys1 <- ConQuestSys()
mySys2 <- ConQuestSys()
mySysList <- list(mySys1, mySys2)
myDifDf <- sysToItemDifDf(mySysList, mySuffixes = c("_male", "_female"), myDims = "all")
myDifPlot <- plotDif (myDifDf,myScale = "centred", mySuffixes = c("_male", "_female"))
## Not run:

# if you run the above example you will have the plot in the object `myDifPlot`.
plot(myDifPlot)
## End(Not run)

See Also

conquestr::sysToItemDifDf()