choice_likelihood: Define and compute choice likelihood
In choicedata: Working with Choice Data

choice_likelihood

R Documentation

Define and compute choice likelihood

Description

These functions prepare and evaluate the likelihood contribution of observed choices for a given choice model.

choice_likelihood() pre-computes the design matrices and choice indices implied by choice_data and choice_effects. The returned object stores these quantities so that repeated likelihood evaluations during maximum likelihood estimation avoid redundant work.
compute_choice_likelihood() evaluates the (log-)likelihood for given choice_parameters. It can either take the original choice objects or a pre-computed choice_likelihood object.

Usage

choice_likelihood(
  choice_data,
  choice_effects,
  choice_identifiers = extract_choice_identifiers(choice_data),
  input_checks = TRUE,
  lower_bound = 1e-10,
  ...
)

compute_choice_likelihood(
  choice_parameters,
  choice_data,
  choice_effects,
  logarithm = TRUE,
  negative = FALSE,
  lower_bound = 1e-10,
  input_checks = TRUE,
  ...
)

Arguments

`choice_data`	[`choice_data`] A `choice_data` object with the observed choices.
`choice_effects`	[`choice_effects`] A `choice_effects` object that determines the model effects.
`choice_identifiers`	[`choice_identifiers`] A `choice_identifiers` object. The default extracts identifiers from `choice_data`.
`input_checks`	[`logical(1)`] Forwarded to `choiceprob_probit` or `choiceprob_logit` to control additional input validation.
`lower_bound`	[`numeric(1)`] The minimum probability used when computing the log-likelihood. Values below this bound are truncated to avoid taking the logarithm of zero.
`...`	Additional arguments passed to `choiceprob_probit` or `choiceprob_logit`.
`choice_parameters`	[`choice_parameters` \| `list`] A `choice_parameters` object or a list as returned by `switch_parameter_space`. When a numeric vector in optimization space is supplied, it is converted via `switch_parameter_space()`.
`logarithm`	[`logical(1)`] Return the log-likelihood? If `FALSE`, the likelihood is returned.
`negative`	[`logical(1)`] Return the negative (log-)likelihood? Useful for minimization routines.

Value

choice_likelihood() returns an object of class choice_likelihood, which is a list containing the design matrices, the choice indices, and the identifiers. compute_choice_likelihood() returns a single numeric value with the (negative) log-likelihood or likelihood, depending on logarithm and negative.

Examples

data(train_choice)

choice_effects <- choice_effects(
  choice_formula = choice_formula(
    formula = choice ~ price | time,
    error_term = "probit"
  ),
  choice_alternatives = choice_alternatives(
    J = 2, alternatives = c("A", "B")
  )
)

choice_data <- choice_data(
  data_frame = train_choice,
  format = "wide",
  column_choice = "choice",
  column_decider = "deciderID",
  column_occasion = "occasionID"
)

likelihood <- choice_likelihood(
  choice_data = choice_data,
  choice_effects = choice_effects
)

choice_parameters <- generate_choice_parameters(choice_effects)

compute_choice_likelihood(
  choice_parameters = choice_parameters,
  choice_data = likelihood,
  choice_effects = choice_effects,
  logarithm = TRUE
)

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