Environmental risk and welfare valuation under imperfect information

Consumers are often uninformed, or unsure, about the ambient level of environmental risk. An optimal policy must jointly determine efficient levels of self-protection, information provision, and public risk mitigation efforts. Unfortunately, conventional welfare measures are not amenable to welfare analysis in the presence of imperfect information. We develop a theoretical welfare measure, called quasi-compensating variation, that is a natural extension of compensating variation (CV). We show that this welfare measure offers not only a money metric of the "value of information," but also a means to appropriately evaluate the welfare effects of various policies when consumers are imperfectly informed about ambient risk. This welfare measure allows us to obtain a number of results that the traditional CV measure fails to offer. In particular, we show that the consumer's willingness to pay for a (small) environmental risk reduction is higher for those who underestimate ambient risk than for those who overestimate or are perfectly informed if the marginal return to self-protection increases with ambient risk.