Directly asks people what they are willing to pay for a benefit an/or willing to receive in compensation for tolerating a cost through a survey or questionnaire. Personal valuations for increases or decreases in the quantity of some good are obtained contingent upon a hypothetical market. The aim is to elicit valuations or bids which are close to what would be revealed if an actual market existed. Several biases, including strategic, design, (starting point, vehicle, and informational), hypothetical, and operational are discussed above and below.