A set of pricing methods where people are asked how much they would agree to pay for avoiding a degradation of the environment or, alternatively, how much they would ask as a compensation for the degradation.
Alternatively, people can be asked to make trade-offs among different alternatives, from which their willingness to pay can be estimated. These methods include contingent valuation which is a direct method and conjoint analysis approaches (contingent ranking, rating, etc.) which are indirect. Both generate welfare estimates of environmental benefits/damages based on stated willingness to pay.