Several valuation methodologies were used including direct valuation, replacement costs, and benefit transfer.
However, it does not offer a direct valuation of forests' role in ameliorating floods.
One issue that has received attention is the selection of the states for direct valuation by respondents.
Relevance: the states selected for direct valuation should be those most frequently reported by the population for which the value set is being developed.
For this study, the values or weights used for all health states were taken from a study with a British general community sample (n = 3,395) using a time-trade-off technique for direct valuation on 42 of them [42].
Through Judgment T-274, the Constitutional Court of Colombia declared that direct valuation studies that had been made in 2002, shortly after the spill, were inadmissible due to lack of objectivity and rigor and ordered that the studies be repeated.
Direct valuation of air quality has as a drawback; that estimated willingness to pay figures cannot be apportioned to the several environmental goods affected by air quality, such as mortality and morbidity effects, visibility, outdoor recreation, among others.
Among direct valuation methods, the choice experiment method (CEM) becomes a highly attractive valuation procedure, in giving at the same time the economic value of the impacts of the different components of the policy as well as the global impact of a policy package.
Bandcamp, in particular has become one such boon for artists, facilitating a direct valuation process for supporters, one that often boasts a a "name your price" tag reminiscent of Radiohead's experimental In Rainbows release.
There are a number of alternative direct valuation techniques.
