Stacked percent bar chart for two categorical variables — plot_2_categorical

Create a stacked percent bar chart of an x categorical variable broken down by a second categorical variable. The plot includes within-group percentages, group sample sizes above each bar, and (optionally) a subtitle showing Cramer's V and the test p-value.

Usage

plot_2_categorical_vars(
  d,
  xvar,
  yvar,
  xvar_label = NULL,
  yvar_label = NULL,
  yvar_colors = NULL,
  title = NULL,
  title_nchar_wrap = 30,
  show_effect_size = TRUE,
  n_pct_size = 3.5,
  inside_bar_stats = c("pct", "n", "pct_and_n", "none"),
  pct_digits = 0,
  plot_horizontal = FALSE,
  flip = FALSE,
  xaxis_labels_nchar_wrap = 20,
  y_max = 110,
  n_ypos = y_max - 5,
  include_overall_bar = FALSE,
  overall_label = "Overall"
)

Arguments

d: A data.frame containing the variables.
xvar: Character scalar, name of the categorical x variable (column in d).
yvar: Character scalar, name of the categorical y variable (column in d).
xvar_label: Optional character scalar to use for the x axis label.
yvar_label: Optional character scalar to use for the legend label.
yvar_colors: Optional character vector of colours to use for the y-variable levels. Must be length equal to nlevels(d[[yvar]]). Provide colour names (e.g. "red") or hex codes (e.g. "#FF0000"). If NULL (default) ggplot2's default palette is used.
title: Optional character scalar for the plot title.
title_nchar_wrap: Integer scalar. Maximum number of characters per line of title.
show_effect_size: Logical; if TRUE the subtitle will include Cramer's V and p-value.
n_pct_size: Numeric scalar. Point size used for the percent labels inside the stacked bars and for the group N labels above bars. Must be a single positive numeric value.
inside_bar_stats: Character scalar controlling what statistics are printed inside the stacked bars. One of "pct" (default; shows within-group percentage), "n" (shows count only), "pct_and_n" (shows percentage with count in parentheses, e.g. "12% (34)"), or "none" (no labels inside bars).
pct_digits: Integer scalar (default 0). Number of decimal places to show for the within-group percent labels (e.g. 0 => "12%", 1 => "12.3%"). Must be a single non-negative numeric value.
plot_horizontal: Logical scalar. Deprecated/alias for flip. If TRUE the plot will be shown with horizontal bars. Prefer using flip.
flip: Logical scalar (default FALSE). If TRUE the plot is flipped to show horizontal bars.
xaxis_labels_nchar_wrap: Integer scalar. Maximum number of characters per line for x-axis group labels. Longer labels will be wrapped to multiple lines.
y_max: Numeric scalar. Maximum y-axis limit for the plot.
n_ypos: Numeric scalar. y-axis position for the group N labels.
include_overall_bar: Logical scalar (default FALSE). If TRUE, a pooled "Overall" bar showing the marginal distribution of yvar across all observations is prepended to the left of the per-group bars, separated by a solid vertical line.
overall_label: Character scalar (default "Overall"). Label used for the pooled bar when include_overall_bar = TRUE.

Value

A list of the ggplot2 object, Cramer's V effect size, p-value.

Examples

data(mtcars)
mtcars$cyl <- factor(mtcars$cyl)
mtcars$gear <- factor(mtcars$gear)
p <- plot_2_categorical_vars(
  d = mtcars,
  xvar = "cyl",
  yvar = "gear",
  xvar_label = 'Cylinders',
  yvar_label = 'Gears'
)
p$ggplot