item_obsexp function

Observed and Expected Item Mean Scores

Homogeneity of item responses in the low and high score groups is analyzed by looking at observed and expected item mean scores together with standardized residuals. If the Andersen's CLR test has shown some evidence against homogeneity, this comparison can indicate which items might be responsible.

item_obsexp(object)

Arguments

• object: An object of class "Rm", a fitted Rasch model or partial credit model using the functions RM or PCM in package eRm, or an object of class "pcmodel", a fitted partial credit model using the function pcmodel in package psychotools.

Returns

list with observed and expected mean scores together with standardized residuals for the two score groups.

Examples

rm.mod <- RM(amts[,4:13])
item_obsexp(rm.mod)
## Not run:

pc.mod <- PCM(desc2[,5:14])
item_obsexp(pc.mod)
## End(Not run)

Author(s)

Marianne Mueller