Willingness to Pay for Quality Improvements: Should Revealed and Stated Preference Data be Combined?

Confidence in the use of the contingent valuation method (CVM) for measuring the value of environmental.goods and services increases substantially when willingness to pay (WTP) estimates from stated preference techniques, CVM, converge with estimates from revealed preference techniques, i.e., the averting behavior, hedonic price, and travel cost methods. Carson et al. [6], in a meta-analysis of the convergent validity literature for quasi-public goods, concluded that WTP estimates from the CVM are of the same order of magnitude and positively and significantly correlated with those from revealed preference techniques. These results suggest that it is inconsequential whether a researcher adopts stated or revealed preference techniques for the measurement of use values for changes in environmental quality.