The benefit transfer method requires the necessary assumption that the
overall population of the study site is similar to that of the project site. The
transferred value must be used for the same kind of environment and the same
terms of value must also be used. For instance, if a tourism benefit of the
environment was estimated in terms of WTP in the study site, it has to be
transferred to the project site as a tourism value in terms of WTP as well. The
value cannot be used for other benefit estimations or as WTA.