A General Model of Starting Point Bias in Double-Bounded Dichotomous Contingent Valuation Surveys

This paper develops a general model that addresses the starting point bias in the dichotomous choice evaluation data by incorporating both the anchoring effect and yea-saying bias. The model is applied to a contingent valuation study that evaluated the health benefits of air quality improvement in three major metropolitan areas in Taiwan. The empirical evidence shows a strong anchoring effect but a weak yea-saying bias. The results show a serious understated willingness to pay if the biases in anchoring and yea-saying are not controlled.