Plot an item's characteristic curves across frames

Plots the model expected-score curve for one item in each frame, with observed class-interval means overlaid. Differences between the model curves reflect the fitted frame units. A nominated non-frame person factor separates the observed means within each frame for a DIF display.

Usage

plot_icc_frames(fit, item, n_groups = NULL, grid = NULL, group = NULL)

Arguments

fit: A fitted object from rasch_efrm.
item: Underlying item name.
n_groups: Number of class intervals for the observed means. By default, use the fit's count, with at least two requested intervals. Tied locations may produce fewer intervals.
grid: Logit grid.
group: Optional person grouping vector, or one or more names of non-frame factors nominated in the fit. Several names define their factor-combination cells.

Value

Called for its plotting side effect; invisibly NULL.

Examples

# \donttest{
# see ?rasch_efrm for a complete simulated example
# }