“Revealed preference methods use existing market data to derive implicit values for a good, for example hedonic pricing, travel costs. Revealed preferences work when the good already exists, albeit indirectly, in the market.”

References

Lusk, J., Shogren, J.F., 2007. Experimental auctions: methods and applications in economic and marketing research, Quantitative methods for applied economics and business research. Cambridge University Press, Cambridge ; New York.