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ECDF Plot Comparing Prior Sensitivity

Source: R/ecdf_prior_plot.R
ecdf_prior_plot.Rd

Creates an empirical cumulative distribution function (ECDF) plot comparing posterior distributions across different prior specifications for a single model type (or small set of model types).

Use this plot to assess how sensitive conclusions are to the choice of prior distributions.

Usage

ecdf_prior_plot(
  model,
  data,
  priors,
  estimand,
  model_types = "random_effect",
  prior_order = NULL,
  prob_reference = "null",
  null_value = NULL,
  null_range = NULL,
  add_null_range = FALSE,
  color_null_range = "#77bb41",
  label_control = "Control",
  label_intervention = "Intervention",
  title = NULL,
  subtitle = NULL,
  xlim = NULL,
  x_breaks = NULL,
  color_palette = NULL,
  linetype_by_model = TRUE,
  show_density = TRUE,
  font = NULL
)

Arguments

model

A fitted bayesma object.

data

A data frame containing the study data used to fit the model.

priors

A named list of prior specifications. Each element must be a list with at least mu_prior and optionally tau_prior, and may include name for display labels.

estimand

Effect estimand string (e.g., "OR", "RR", "HR", "IRR", "MD", "SMD").

model_types

Character vector specifying which model type(s) to include. Maximum of 2 model types to avoid clutter. Valid values: "common_effect", "random_effect", "bias_corrected", "selection_copas", "selection_weight", "pet_peese", "robust", "robma". Default is "random_effect".

prior_order

Optional character vector specifying the display order of priors. Should contain the names (IDs) of the priors in the desired order. If NULL, priors are displayed in the order they appear in priors.

prob_reference

Character string. What reference to use for probability axis labels. Either "null" (compare to null_value) or "null_range" (compare to null_range boundaries). Default is "null".

null_value

Null hypothesis value. If NULL, uses estimand default.

null_range

Numeric vector of length 2 giving null range bounds.

add_null_range

Logical. If TRUE and null_range is NULL, uses estimand-appropriate defaults.

color_null_range

Fill colour for the null range band. Default "#77bb41".

label_control

Label for control group. Default "Control".

label_intervention

Label for intervention group. Default "Intervention".

title

Optional plot title.

subtitle

Optional plot subtitle. If NULL and a single model type is selected, displays the model type.

xlim

Optional x-axis limits.

x_breaks

Optional x-axis break points.

color_palette

Optional named vector of colours for priors.

linetype_by_model

Logical. If TRUE and multiple model types are selected, uses different linetypes for each model type. Default TRUE.

show_density

Logical. If TRUE, includes a density plot below the ECDF. Default is TRUE.

font

Optional font family.

Value

A ggplot object (or patchwork object if show_density = TRUE).

Details

The plot shows one ECDF line per prior specification (and per model type if multiple are selected). This allows direct comparison of how different prior choices affect the posterior distribution.

When two model types are selected, colour represents prior and linetype represents model type, allowing comparison of both dimensions simultaneously.

The left y-axis shows P(effect < x) and the right y-axis shows P(effect > x).

See also

ecdf_model_plot for comparing models within a prior.