An Investigation of Part-Whole Biases in Contingent-Valuation Studies

Part-whole bias is a possible explanation for nonuse contingent-valuation estimates that are insensitive to marginal changes in environmental commodities. Our empirical analyses reveal no statistically significant differences in willingness to pay of independent samples of nonusers to prevent 2000, 20,000, or 200,000 migratory waterfowl deaths in the Central Flyway, all numbers less than 2% of the waterfowl population. Five alternative propositions for explaining this empirical findings do not provide a completely satisfactory explanation. More research is necessary to investigate appropriate commodity metrics, sample sizes for small changes in environmental commodities, and consider how respondents evaluate small changes in environmental commodities.