Cognitive Ability and Scale Bias in the Contingent Valuation Method

This study investigates whether or not the scale bias found in contingent valuation (CVM) studies on mortality risk reductions is a result of cognitive constraints among respondents. Scale bias refers to insensitivity and non near-proportionality of the respondents' willingness to pay (WTP) to the size of the risk reduction. Two hundred Swedish students participated in an experiment where their cognitive ability was tested before they took part in a CVM-study where they were asked about their WTP to reduce bus-mortality risk. The results imply that WTP answers from respondents with a higher cognitive ability are less flawed by scale bias.