Stated preference methods are closely related to those used in marketing studies trying to determine whether consumers will buy a new good not yet on the shelves. For instance, consider when personal mp3 players did not yet exist, but people had portable compact disk players. How might the methods of contingent valuation or conjoint analysis be used to determine whether people would buy a personal mp3 player? What, if anything, is different about using these methods for environmental goods compared to goods that can be marketed but are not yet on the market?