Returns the computed WTP from a preference space model.
wtp(object, scalePar)is an object of class logitr (a model estimated using
the 'logitr()` function).
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".
A data frame of the WTP estimates.
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.
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 0.366555 0.024383 15.0330 < 2.2e-16 ***
#> feat 1.340699 0.359390 3.7305 0.0001911 ***
#> brandhiland -10.136219 0.584836 -17.3317 < 2.2e-16 ***
#> brandweight -1.749094 0.181226 -9.6514 < 2.2e-16 ***
#> brandyoplait 2.003848 0.143034 14.0096 < 2.2e-16 ***
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1