Valuing hemlock woolly adelgid control in public forests: scope effects with attribute non-attendance.
Sensitivity to the scope of public good provision is an important indication of validity for the contingent valuation method. Despite advances in survey methods, not every contingent valuation study passes the scope test. One explanation may be attribute non-attendance, which arises when survey respondents ignore choice attributes for a variety of reasons. We compare bounded and repeated referendum contingent valuation questions with and without consideration of stated and inferred ANA. An online survey was administered to an opt-in, or non-probability sample, panel in September 2017 to estimate the willingness-to-pay to protect hemlock trees from a destructive invasive species on federal land in North Carolina. We collected survey responses from 907 North Carolina residents. We estimate the probability of a yes vote in a referendum to treat for hemlock woolly adelgid infestation in a given acreage of ecologically important and socially important areas, using either chemical or biological controls, for a given annual cost for a three year period. We find evidence that attribute non-attendance is a factor when testing for sensitivity to scope. When estimating the model with stated attribute non-attendance the ecologically and socially important scope coefficients become positive and statistically significant. We find several differences between the bounded and repeated sequential contingent valuation data samples.