Closed and bounded question

Interrogation method consisting in asking a first valuation question such as "Would you be willing to pay €10 for ...?" and a second in which the proposed amount depends on the answer to the first question: greater amount if the answer to the first question is "yes", smaller otherwise. For the contingent valuation method, asking a closed bounded question may be tricky in a mail survey. The mail survey does not necessarily preclude such questioning but its use is usually not recommended.