er_style_group: Group panel builders for exposure-response plots

In erplots: Model-Agnostic Exposure-Response Plots

Group panel builders for exposure-response plots

Description

Builder functions for the group layer (er_plot_add_groups()), drawing the exposure distribution for a grouping variable as a boxplot, violin, or histogram panel.

Usage

er_style_group_boxplot(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  alpha = 0.5,
  show_outliers = TRUE,
  ...
)

er_style_group_histogram(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  bins = 30,
  alpha = NULL,
  ...
)

er_style_group_violin(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  alpha = 0.5,
  quantiles = NULL,
  quantile_linetype = "solid",
  ...
)

er_style_group_linerange(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  scale_factor = 1,
  inner_range = c(0.25, 0.75),
  outer_range = c(0.05, 0.95),
  dot_alpha = 1,
  inner_alpha = 0.8,
  outer_alpha = 0.4,
  ...
)

er_style_group_boxjitter(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  alpha = 0.5,
  jitter_height = 0.15,
  jitter_size = 1,
  jitter_alpha = 0.6,
  ...
)

er_style_group_violinjitter(
  data,
  config,
  stratify,
  exposure,
  response,
  strata,
  theme,
  alpha = 0.5,
  quantiles = NULL,
  quantile_linetype = "solid",
  jitter_height = 0.15,
  jitter_size = 1,
  jitter_alpha = 0.6,
  ...
)

Arguments

data	The original data frame.
config	Configuration for the specific plot.
stratify	Logical: whether to stratify.
exposure	Exposure variable.
response	Response variable.
strata	Stratification variable.
theme	Theme components.
alpha	Transparency of the geom. Defaults to 0.5 for er_style_group_boxplot()/er_style_group_violin()/ er_style_group_boxjitter()/er_style_group_violinjitter(); er_style_group_histogram() defaults to NULL, which resolves to 0.5 when stratified or 0.8 otherwise.
show_outliers	Logical: whether er_style_group_boxplot() draws the boxplot's own outlier points. Defaults to TRUE; er_style_group_boxjitter() sets this to FALSE when it wraps this builder, since its own jittered points already show every raw value, outliers included.
...	Additional named arguments forwarded from er_plot_add_groups()'s own .... er_style_group_boxjitter()/er_style_group_violinjitter() read a seed from here (NULL when not supplied) and use it to scope (via withr::with_seed()) the vertical jitter draw, letting a caller make the jitter reproducible across repeated plot() calls on the same object – the same opt-in-only mechanism er_style_data_overlay()/er_style_data_boxjitter() use for the data layer (see er_style_data()); with no seed, each render draws a fresh jitter.
bins	Number of histogram bins for er_style_group_histogram(). Defaults to 30.
quantiles, quantile_linetype	Violin quantile positions and linetype for er_style_group_violin(). Default to NULL (no quantile lines drawn) and "solid" respectively.
scale_factor	Overall size multiplier for er_style_group_linerange()'s dot and lines. Defaults to 1.
inner_range, outer_range	Quantile probabilities (length 2) for er_style_group_linerange()'s thick and thin lines. Default to c(0.25, 0.75) and c(0.05, 0.95) respectively.
dot_alpha, inner_alpha, outer_alpha	Per-part transparency for er_style_group_linerange()'s dot, inner line, and outer line. Default to 1, 0.8, and 0.4 respectively.
jitter_height, jitter_size, jitter_alpha	Vertical jitter, point size, and transparency for er_style_group_boxjitter()/er_style_group_violinjitter()'s overlaid points. Default to 0.15, 1, and 0.6 respectively.

Details

See er_style() for the shared builder interface these functions implement.

Value

A geom, or a list of geoms; see er_style().

Choosing a builder

All six builders show the same thing – a grouping variable's exposure distribution – as one of a few visual idioms:

• er_style_group_boxplot() (the default) – a boxplot, group levels on the y-axis.

• er_style_group_violin() – a violin instead of a boxplot, same axis layout.

• er_style_group_histogram() – group levels on facet strips instead, freeing the y-axis for counts.

• er_style_group_linerange() – a median dot flanked by an inner-range and outer-range line, instead of a full boxplot/violin shape; same y-axis layout as the boxplot/violin builders.

• er_style_group_boxjitter() / er_style_group_violinjitter() – thin wrappers around er_style_group_boxplot()/ er_style_group_violin() that additionally overlay jittered raw exposure values (see "Jittered variants" below).

All built-in group builders are tagged layer = "plot_group", so er_plot_add_groups() errors if given one tagged for another layer.

Axis and facet layout

er_style_group_boxplot() and er_style_group_violin() put group levels on the y-axis; er_style_group_histogram() puts them on facet strips and frees the y-axis for counts; er_style_group_linerange() also puts group levels on the y-axis, summarising each level's exposure distribution as a median dot flanked by an inner-range and outer-range line rather than a full boxplot/violin shape.

Jittered variants

er_style_group_boxjitter()/er_style_group_violinjitter() are thin wrappers around er_style_group_boxplot()/er_style_group_violin() that additionally overlay jittered raw exposure values (vertical jitter only – exposure position on the x-axis is never perturbed), the same idea er_style_data_boxjitter() applies to the data layer.

See Also

er_style()

Examples

if (requireNamespace("erglm", quietly = TRUE)) {
  library(erglm)
  mod <- erglm_model(ae1 ~ aucss, erglm_data, family = binomial())

  # er_style_group_boxplot(): the default
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_boxplot) |>
    plot()

  # er_style_group_violin(): a violin instead of a boxplot
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_violin) |>
    plot()

  # er_style_group_histogram(): group levels on facet strips, with
  # the y-axis freed for counts
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_histogram) |>
    plot()

  # er_style_group_linerange(): median dot + inner/outer range lines,
  # instead of a full boxplot/violin shape
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_linerange) |>
    plot()

  # er_style_group_boxjitter(): the boxplot, with jittered raw
  # exposure values overlaid on top
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_boxjitter) |>
    plot()

  # er_style_group_violinjitter(): the violin, with jittered raw
  # exposure values overlaid on top
  erglm_data |>
    er_plot(aucss, ae1) |>
    er_plot_add_model(mod) |>
    er_plot_add_groups(aucss, style = er_style_group_violinjitter) |>
    plot()
}

erplots documentation built on Oct. 4, 2026, 5:06 p.m.