Two costs are associated with visiting a recreational site: the opportunity cost of time and the travel cost. This research examines the robustness of various estimates of the opportunity cost of time in order
to more accurately estimate the willingness to pay for wetland restoration at Maumee Bay State Park. Samples are drawn from the Northwest Ohio Wetland Survey, which was conducted in 2008. Because employment classification reveals information about the individual's opportunity cost of time, respondents were split into subgroups based on their employment classification. An individual can be out of the labor market, work a fixed schedule and be underemployed, work a fixed schedule and be overemployed, or an individual can be free to choose their work hours. I also allow for the possibility that an individual working a fixed schedule is content working their current hours.
Models using different discount rates, k, were used to estimate the sensitivity of the willingness to pay estimate to various measures of the opportunity cost of time. Using estimates from a bivariate Poisson
lognormal model, the willingness to pay estimates varied significantly, from $14.91 per person per year when k=0 to $56.42 per person per year when k=1, depending on the opportunity cost of time. Allowing k to vary by employment subgroup leads to a willingness to pay estimate of $26.40, which was similar to the estimate calculated when k was 1/3.