Hk approach is based upon the idea that a life should be measured by an individual 's potentials for future production , and wtp approach upon the idea that value of life can be estimated by the quantity of money a person would be willing to pay to reduce the risk of death .
One commonly used method in contingent valuation ( cv ) survey for wtp ( willingness-to-pay ) is the " double-bound dichotomous choice approach " and an implicit assumption is that all study subjects are willing to pay a reasonable price .