A variety of questioning formats have been used in contingent-valuation studies, with dichotomous-choice questions becoming the preferred format. However, as with any empirical technique, continued applications raise questions that require attention if the credibility of the procedure is to be...

Contingent valuation is used to measure the benefits of a proposed public program to control black flies. Respondents' reported values are analyzed from three perspectives: data outliners, consistency between respondents' reported values and their perceptions of black flies, and the temporal...