Groups examinees by their ability estimate and compares the observed mean item score in each group (with 95% intervals) with the model-implied curve. Large departures point to misfit.
Usage
gg_empirical(x, item, bins = 10, theta_lim = c(-3, 3))Arguments
- x
a unidimensional model returned by
mirt::mirt().- item
a single item, by position or name.
- bins
number of ability groups.
- theta_lim
range of the latent trait.
Examples
mod <- mirt(expand.table(LSAT7), 1, verbose = FALSE)
gg_empirical(mod, 1)
