Stated preference methods remain the only means capable of estimating non-use values yet can suffer from many types of well-known biases. We construct an approach to identify the role of social desirability bias, relative to other potential survey biases, using a stated preference survey for improving the status of species at risk. The survey respondents were asked how they would vote, how they think their fellow survey participants would vote, as well as how they think people in their region would vote in an actual referendum. We find that willingness-to-pay estimates for public good (passive use) values differ across these vote question types. Our results demonstrate how stated preference practitioners can use multiple referent groups to help disentangle social desirability bias from other survey biases.

Travel cost models using the wage rate to value time make the implicit assumption that the value of time is equalized throughout the year. We develop a seasonal travel cost model that allows the value of time to vary by season. We estimate the model using data from a survey of recreational anglers in the Gulf of Mexico. We find that people’s value of time is 55% larger on average in the summer compared to other times of year and find substantial differences in derived welfare estimates if a time-constant value of time measure is used instead.