our survey
was organized into three steps (the pretest, pilot test and formal
test) to make the questionnaires easier to understand. An openended (OE) questionnaire was used for the pretest to supply
more information when revising the questionnaire. A payment card
(PC) questionnaire was used in the pilot test to evaluate the effectiveness of the questionnaire and to obtain the appropriate
entrance fee. These two tests were administered to 110 individuals
with different backgrounds in the study areas from June 1st to 10th
2010. In the formal test, a dichotomous choice (DC) CVM, which
have been suggested as an effective alternative method, was chosen