On mechanisms eliciting ordinal preferences

• 成果类型: Article
• 署名作者: Carroll, Gabriel
• 署名单位: Stanford University
• 刊物名称: THEORETICAL ECONOMICS
• ISSN/ISSBN: 1555-7561
• DOI: 10.3982/TE2774
• 发表日期: 2018-09-01
• 页码: 1275-1318
• 关键词: Cardinal extension; ex post implementation; interdependence; ordinal mechanism; robust mechanism design

摘要

When is a mechanism designer justified in only asking for ordinal information about preferences? Simple examples show that even if the planner's goal (expressed by a social choice correspondence (SCC)) depends only on ordinal information, eliciting cardinal information may help with incentives. However, if agents may be uncertain about their own cardinal preferences, then a strong robustness requirement can justify the focus on ordinal mechanisms. Specifically, when agents' preferences over pure outcomes are strict, if a planner is able to implement an SCC (in ex post equilibrium) using a mechanism that is robust to interdependence of arbitrary form in cardinal preferences, then there must exist such a mechanism that elicits only ordinal preferences. The strictness assumption can be dropped if we further allow the possibility of non-expected-utility preferences.