Cultural bias in contingent valuation of copper mining in the Commonwealth of Dominica

Cultural bias in contingent valuation exists if groups within a population have a cultural predisposition toward answering "no" or "yes" to questions which causes the population estimate of the WTP to be underestimated or overestimated. This study estimated cultural bias through the valuation of environmental resources threatened by copper mining on the island of Dominica. The results rejected the null hypotheses of identical social characteristics and similar answers to binary response questions by the four social groups. The Caribs answered "no" significantly more than other Dominicans. The mean WTP of the Caribs was below 0.16 of the values for the other groups. However, for the Caribs, their WTP as a percentage of their annual income was more than twice that of visitors, suggesting income was not a factor affecting the WTP. Population WTP, as the aggregate of separate group estimates of the WTP was equal to EC$152.40Â million. However, population WTP estimated from a single sample from the whole population was EC$110.15Â million. Thus, the cultural bias was estimated at EC$-41.64Â million, reducing the population WTP by 27.33%. Care is therefore needed in sampling social groups and estimating population WTP in contingent valuation studies, especially in developing countries.