check_form: Check model formula

In RprobitB: Bayesian Probit Choice Modeling

Check model formula

Description

This function checks the input form.

Usage

check_form(form, re = NULL, ordered = FALSE)

Arguments

form	[formula] A model description with the structure choice ~ A | B | C, where choice is the name of the dependent variable (the choices), A are names of alternative and choice situation specific covariates with a coefficient that is constant across alternatives, B are names of choice situation specific covariates with alternative specific coefficients, and C are names of alternative and choice situation specific covariates with alternative specific coefficients. Multiple covariates (of one type) are separated by a + sign. By default, alternative specific constants (ASCs) are added to the model. They can be removed by adding +0 in the second spot. In the ordered probit model (ordered = TRUE), the formula object has the simple structure choice ~ A. ASCs are not estimated.
re	[character() | NULL] Names of covariates with random effects. If re = NULL (the default), there are no random effects. To have random effects for the ASCs, include "ASC" in re.
ordered	[logical(1)] If TRUE, the choice set alternatives is assumed to be ordered from worst to best.

Value

A list that contains the following elements:

• The input form.

• The name choice of the dependent variable in form.

• The input re.

• A list vars of three character vectors of covariate names of the three covariate types.

• A boolean ASC, determining whether the model has ASCs.

See Also

overview_effects() for an overview of the model effects

RprobitB documentation built on Aug. 26, 2025, 1:08 a.m.