“””…stated preference methods use public opinion surveys or comparative choice trials that ask a person, directly or indirectly, to state his or her value for the new good or service. The upside of stated preference methods is that the researcher can create a hypothetical market where a person can, in theory, buy or sell any good or service. The stated preference method is flexible enough to construct alternative potential scenarios such that demand for the good can be understood given changes in market and non-market conditions. A well known downside of stated preference methods, regardless of how well the survey is designed and executed, is that people know they are valuing a
hypothetical change in the good or service.”””

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.