Biased valuations, damage assessments, and policy choices: The choice of measure matters

Damages from, for example, an oil spill can be measured by how much people are willing to pay to avoid them, or by the minimum compensation they demand to accept them; and decisions to clean up can be justified by the willingness to pay to do it or by the compensation necessary to forgo it. Contrary to the usual official and unofficial conventions that the choice of measure is of no matter, the empirical evidence and intuitions of most people strongly suggest otherwise. The appropriate choice of measure appears to turn, not on legal entitlements, but on the reference state people use to judge negative and positive changes - a criteria that is likely to call into question most estimates of the damages of increased health risks and the value of environmental mitigation efforts.