Part-Whole Bias in Contingent Valuation: Will Scope Effects Be Detected with Inexpensive Survey Methods?

The purpose of this paper is to test for scope effects with the contingent valuation method. We use data from a telephone survey focusing on water quality improvements in the Albemarle and Pamlico Sounds in North Carolina. We find that the willingness to pay estimates are sensitive to the scope of the policy. These results suggest that the use of inexpensive survey methods may not be the cause of the failure to detect scope effects in some recent contingent valuation studies.