Normal quantile-quantile plot of person standardized residuals

Produces a Q-Q plot of per-person standardized residuals. Under the fitted Rasch-family model the residuals are approximately N(0, 1), so deviations from the reference line diagnose distributional misfit that mean-square summaries may miss.

Usage

plot_residual_qq(
  fit,
  diagnostics = NULL,
  preset = c("standard", "publication", "compact", "monochrome"),
  draw = TRUE
)

Arguments

fit: An mfrm_fit.
diagnostics: Optional diagnose_mfrm() output; required entries are generated internally when absent.
preset: Visual preset.
draw: If TRUE, draw with base graphics.

Value

An mfrm_plot_data object with a data slot containing Person, Theoretical, Sample columns.

Session plot defaults

Set options(mfrmr.plot_preset = "publication") to choose a session default for plotting functions that expose the common preset argument. The supported values are "standard", "publication", "compact" and "monochrome". Precedence is an explicit call argument, then the session option, then "standard". For example, preset = "standard" overrides a session set to "monochrome". Explicit preset = NULL retains the earlier package-default behavior; it does not read the session option. Invalid session values cause an error only when that option is needed.

The category-curve, data-quality, fit-review, connectivity and network routes of plot() for report bundles use the same option through .... Plots without a common preset argument, including extended-model plots with their own palette controls, keep their own settings. This option selects a preset, not a universal theme or a guarantee that all renderers implement every appearance control identically.

New plot payloads retain the resolved preset for supported saved-data rendering. Converting an existing payload with as_ggplot() uses its saved appearance, even after the session option changes. A call that creates a new plot from a fit or statistical result uses the current default. For a reproducible script, supply preset explicitly or set the option in that script. Saving only the fitted model does not save a session option. No global ggplot theme is changed.

Restore previous settings with old <- options(mfrmr.plot_preset = "monochrome") followed by options(old). Use options(mfrmr.plot_preset = NULL) to remove the option. The preset changes appearance, not estimates, confidence levels or diagnostic thresholds.

Examples

# \donttest{
toy <- load_mfrmr_data("example_core")
fit <- fit_mfrm(toy, "Person", c("Rater", "Criterion"), "Score",
                method = "JML", maxit = 300)
p <- plot_residual_qq(fit, draw = FALSE)
head(p$data$data)
#>   Person Theoretical      Sample
#> 1   P023   -2.310991 -0.37251225
#> 2   P002   -1.862732 -0.13615852
#> 3   P032   -1.624981 -0.10407482
#> 4   P005   -1.454408 -0.10235602
#> 5   P008   -1.318011 -0.08876509
#> 6   P004   -1.202508 -0.08291038
# Look for: points hugging the y = x reference line. Heavy upper-
#   right tails indicate persons whose residual aggregates exceed
#   the standard normal expectation; pair with `plot_unexpected()`
#   for case-level follow-up. This is an exploratory screen; do
#   not treat tail behaviour as a definitive normality test.
# }