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Plot a test-equating comparison

Source: R/equating.R
plot_equate.Rd

Scatter of the two calibrations' common-item locations with the shifted identity line, per-item 95 per cent contrast intervals, and a dotted guide band at their average half-width; drifting items (Holm-adjusted) are highlighted and labelled.

Usage

plot_equate(fit, reference, shift = c("mean", "none"), independent = NULL)

Arguments

fit

A fitted object from rasch.

reference

A second rasch fit, or a data frame with columns item, location, and optionally se; a polytomous bank also needs max.

shift

Passed to equate_tests.

independent

Passed to equate_tests.

Value

Called for its plotting side effect; invisibly the equate_tests result.

Examples

set.seed(1); d <- seq(-1.5, 1.5, length.out = 8)
mk <- function() {
  X <- matrix(rbinom(400 * 8, 1, plogis(outer(rnorm(400), d, "-"))), 400, 8)
  colnames(X) <- paste0("I", 1:8); rasch(X)
}
plot_equate(mk(), mk(), independent = TRUE)