Consumers frequently exchange private data about themselves for goods or for money. For example, they provide personal data in online interactions with technology companies, in return for information or other goods. We provide a normative criterion to assess whether companies adequately...

Economists, psychologists, and marketing researchers rely on measures of consumers' willingness to pay (WTP) in estimating demand for private and public goods and in designing optimal price schedules. Existing market research techniques for measuring WTP differ in whether they provide an...