Get WTP estimates a preference space model

Returns the computed WTP from a preference space model.

Usage

wtp(object, scalePar)

Arguments

object

is an object of class logitr (a model estimated using the logitr() function).

scalePar

The name of the column that identifies the scale variable, which is typically "price" for WTP space models, but could be any continuous variable, such as "time".

Value

A data frame of the WTP estimates.

Details

Willingness to pay is computed by dividing the estimated parameters of a utility model in the "preference" space by the scale parameter, which is should be price to obtain WTP estimates. Uncertainty is handled via simulation.

Examples

library(logitr)

# Estimate a preference space model
mnl_pref <- logitr(
  data    = yogurt,
  outcome = "choice",
  obsID   = "obsID",
  pars    = c("price", "feat", "brand")
)
#> Running model...
#> Done!

# Compute the WTP implied from the preference space model
wtp(mnl_pref, scalePar = "price")
#>                Estimate Std. Error  z-value  Pr(>|z|)    
#> scalePar       0.366584   0.024345  15.0582 < 2.2e-16 ***
#> feat           1.340574   0.358184   3.7427 0.0001821 ***
#> brandhiland  -10.135727   0.585196 -17.3202 < 2.2e-16 ***
#> brandweight   -1.749077   0.181612  -9.6308 < 2.2e-16 ***
#> brandyoplait   2.003825   0.143157  13.9973 < 2.2e-16 ***
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1