index_plot: Index Plot of an Arbitrary Statistic

In semfindr: Influential Cases in Structural Equation Modeling

Index Plot of an Arbitrary Statistic

Description

A generic index plot function for plotting values of a column # in a matrix.

Usage

index_plot(
  object,
  column = NULL,
  plot_title = "Index Plot",
  x_label = NULL,
  cutoff_x_low = NULL,
  cutoff_x_high = NULL,
  largest_x = 1,
  absolute = FALSE,
  point_aes = list(),
  vline_aes = list(),
  hline_aes = list(),
  cutoff_line_aes = list(),
  case_label_aes = list()
)

Arguments

object	A matrix-like object, such as the output from influence_stat(), est_change(), est_change_raw(), and their counterparts for the approximate approach.
column	String. The column name of the values to be plotted.
plot_title	The title of the plot. Default is "Index Plot".
x_label	The Label for the vertical axis, for the value of column. Default is NULL. If NULL, then the label is changed to "Statistic" if absolute is FALSE, and "Absolute(Statistics)" if absolute is TRUE.
cutoff_x_low	Cases with values smaller than this value will be labeled. A cutoff line will be drawn at this value. Default is NULL. If NULL, no cutoff line will be drawn for this value.
cutoff_x_high	Cases with values larger than this value will be labeled. A cutoff line will be drawn at this value. Default is NULL. If NULL, no cutoff line will be drawn for this value.
largest_x	The number of cases with the largest absolute value on 'column“ to be labelled. Default is 1. If not an integer, it will be rounded to the nearest integer.
absolute	Whether absolute values will be plotted. Useful when cases are to be compared on magnitude, ignoring sign. Default is FALSE.
point_aes	A named list of arguments to be passed to ggplot2::geom_point() to modify how to draw the points. Default is list() and internal default settings will be used.
vline_aes	A named list of arguments to be passed to ggplot2::geom_segment() to modify how to draw the line for each case in the index plot. Default is list() and internal default settings will be used.
hline_aes	A named list of arguments to be passed to ggplot2::geom_hline() to modify how to draw the horizontal line for zero case influence. Default is list() and internal default settings will be used.
cutoff_line_aes	A named list of arguments to be passed to ggplot2::geom_hline() to modify how to draw the line for user cutoff values. Default is list() and internal default settings will be used.
case_label_aes	A named list of arguments to be passed to ggrepel::geom_label_repel() to modify how to draw the labels for cases marked (based on arguments such as cutoff_x_low or largest_x). Default is list() and internal default settings will be used.

Details

This index plot function is for plotting any measure of influence or extremeness in a matrix. It can be used for measures not supported with other functions.

Like functions such as gcd_plot() and est_change_plot(), it supports labelling cases based on the values on the selected measure (originaL values or absolute values).

Users can also plot cases based on the absolute values. This is useful when cases are to be compared on magnitude, ignoring the sign.

Value

A ggplot2 plot. Plotted by default. If assigned to a variable or called inside a function, it will not be plotted. Use plot() to plot it.

Author(s)

Shu Fai Cheung https://orcid.org/0000-0002-9871-9448.

See Also

influence_stat(), est_change(), est_change_raw()

Examples

library(lavaan)
dat <- pa_dat
# The model
mod <-
"
m1 ~ a1 * iv1 + a2 * iv2
dv ~ b * m1
a1b := a1 * b
a2b := a2 * b
"
# Fit the model
fit <- lavaan::sem(mod, dat)
summary(fit)

# --- Leave-One-Out Approach

# Fit the model n times. Each time with one case removed.
# For illustration, do this only for selected cases.
fit_rerun <- lavaan_rerun(fit, parallel = FALSE,
                          to_rerun = 1:10)
# Get all default influence stats
out <- influence_stat(fit_rerun)

# Plot case influence on chi-square. Label the 3 cases with the influence.
index_plot(out, "chisq", largest_x = 3)

# Plot absolute case influence on chi-square.
index_plot(out, "chisq", absolute = TRUE)

semfindr documentation built on April 3, 2025, 5:58 p.m.