er_vpc_add_simulated: Add the simulated-data layer to a VPC plot

In erplots: Model-Agnostic Exposure-Response Plots

Add the simulated-data layer to a VPC plot

Description

Bins the simulation data for a VPC plot and computes binned response summaries for comparison against the observed data layer.

Usage

er_vpc_add_simulated(
  object,
  model = NULL,
  sim = NULL,
  style = er_style_vpc_simulated_mean_errorbar,
  nsim = 100,
  seed = NULL,
  simulate_args = list(),
  ...
)

Arguments

object	Partially constructed VPC (has S3 class er_vpc), which must already have an observed layer (see er_vpc_add_observed()).
model	A fitted model implementing er_simulate() with sim_resp. Mutually exclusive with sim.
sim	Simulated data with matching exposure/response/plot_by columns and sim_id. Mutually exclusive with model.
style	Style used to draw the VPC simulation layer. Can either be a string corresponding to one of the registered style labels (e.g., "mean_errorbar", the default), or a builder function used to compute the relevant plot object (see "Styles" below).
nsim	Number of simulation replicates, only used with model. Defaults to 100.
seed	Optional RNG seed. Used for model's own simulation draws, and also (regardless of whether sim/model was supplied) to seed this layer's random tie-break when er_vpc()'s ties is "split-even" – see er_vpc()'s own seed argument for the observed layer's independent tie-break seed.
simulate_args	A named list of additional arguments forwarded to er_simulate() when simulating from the model.
...	Additional named arguments forwarded to the style builder function when the plot is built.

Details

sim and model are mutually exclusive; supply exactly one. model is preferred when it implements er_simulate() with sim_resp, since a VPC needs response-level simulated observations rather than only mean predictions – this function errors informatively if sim_resp isn't available.

conf_level/probs are set once on er_vpc() itself (rather than here), so the observed and simulated layers always agree on them.

Value

object, with object$layer$simulated populated.

Styles

The following pre-defined styles are available for this layer. Please see the documentation for the corresponding builder function to see what customisation options are available:

Label	Builder	Description
"mean_errorbar"	er_style_vpc_simulated_mean_errorbar()	Mean/rate + CI per bin, x-position adaptive to plot_by's type (the default).
"quantile_ribbon"	er_style_vpc_simulated_quantile_ribbon()	One ribbon per requested percentile against a continuous plot_by axis.
"quantile_errorbar"	er_style_vpc_simulated_quantile_errorbar()	Point + error bar per bin and per requested percentile.

See er_style_vpc() for details on how style builder functions are defined for the VPC mini-grammar, should a custom style be required.

See Also

er_vpc(), er_vpc_add_observed(), er_style_vpc_simulated()

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