choice_effects: Define choice model effects

In choicedata: Working with Choice Data

Define choice model effects

Description

This function constructs an object of class choice_effects, which defines the effects of a choice model.

Usage

choice_effects(
  choice_formula,
  choice_alternatives,
  choice_data = NULL,
  delimiter = "_"
)

## S3 method for class 'choice_effects'
print(x, ...)

Arguments

choice_formula	[choice_formula] A choice_formula object.
choice_alternatives	[choice_alternatives] A choice_alternatives object.
choice_data	[NULL | choice_data] A choice_data object. Required to resolve data-dependent elements in choice_formula (if any).
delimiter	[character(1)] The delimiter between covariate and alternative name.
x	[choice_effects] The choice_effects object to be printed.
...	Currently not used.

Value

A choice_effects object, which is a data.frame, where each row is a model effect, and columns are

1. "effect_name", the name for the effect which is composed of covariate and alternative name,

2. "generic_name", the generic effect name "beta_<effect number>",

3. "covariate", the (transformed) covariate name connected to the effect,

4. "alternative", the alternative name connected to the effect (only if the effect is alternative-specific),

5. "as_covariate", indicator whether the covariate is alternative-specific,

6. "as_effect", indicator whether the effect is alternative-specific,

7. "mixing", a factor with levels in the order

   1. "cn" (correlated normal distribution),

   indicating the type of random effect.

For identification, the choice effects are ordered according to the following rules:

1. Non-random effects come before random effects.

2. According to the ordering of the factor mixing.

3. Otherwise, the order is determined by occurrence in formula.

It contains the arguments choice_formula, choice_alternatives, and delimiter as attributes.

Examples

choice_effects(
  choice_formula = choice_formula(
    formula = choice ~ price | income | I(comfort == 1),
    error_term = "probit",
    random_effects = c(
      "price" = "cn",
      "income" = "cn"
     )
  ),
  choice_alternatives = choice_alternatives(J = 3)
)

choicedata documentation built on Nov. 5, 2025, 5:46 p.m.