Introduction

Mixed logit and probit models allow random coefficients whose distribution in the population is estimated. Consider, for example, the model in Chapter 6, of anglers' choice among fishing sites. The sites are differentiated on the basis of whether campgrounds are available at the site. Some anglers like having campgrounds at the fishing sites, since they can use the grounds for overnight stays. Other anglers dislike the crowds and noise that are associated with campgrounds and prefer fishing at more isolated spots. To capture these differences in tastes, a mixed logit model was specified that included random coefficients for the campground variable and other site attributes. The distribution of coefficients in the population was estimated. Figure 11.1 gives the estimated distribution of the campground coefficient. The distribution was specified to be normal. The mean was estimated as 0.116, and the standard deviation was estimated as 1.655. This distribution provides useful information about the population. For example, the estimates imply that 47 percent of the population dislike having campgrounds at their fishing sites, while the other 53 percent like having them.

The question arises: where in the distribution of tastes does a particular angler lie? Is there a way to determine whether a given person tends to like or dislike having campgrounds at fishing sites?