Collaborative Research: Policy Analysis by Revealed Preference: With an Application to Food Security

世界各国政府将预算的很大一部分用于私人物品的公共供应。因此，理解现金和实物再分配之间的权衡是政府政策的核心。例如，实物再分配可能会减少选择，从而降低受援者的福利，但如果纳税人有家长式的偏好，更关心防止饥饿而不是穷人的其他愿望，则可能会增加纳税人的福利。 项目执行人建议进行严格的实验研究，以估计（一）受益人对等值现金和实物转让的偏好，（二）现金和实物转让对营养的相对影响，以及（三）受益人对实物福利的估价。这种设计允许人们衡量受益人的偏好（使用接受率）以及现金与实物福利对营养的因果影响（使用随机分配的报价来估计意向治疗和治疗对治疗的营养影响）。此外，参与者指数还为随机选择的其他家庭提供了以实物福利换取试验性的各种现金转移的选择，这使得能够估计各种价格下对现状的需求，并量化受益人从实物福利相对于现金转移中获得的消费者剩余（或损失）。在方法论上，PI在一个设计中整合了主导现代政策评估的两种范式，一种基于影响，另一种基于显示的偏好。此外，通过测量在随机变化的价格接受，PI是第一批使用实验数据来估计个人层面的受益人对公共提供的私人物品的估价。显示偏好办法的独特之处在于，它使人们能够理解和适应受益人对现金和实物福利的偏好的多样性，从而减少在穷人粮食安全等关键领域进行政策试验的政治和道德风险。

Governments around the world spend large shares of their budgets on the public provision of private goods. Understanding the tradeoffs between redistribution in cash and in kind is thus central to government policy. For example, redistributing in-kind may potentially reduce choice and thus lower recipients' welfare, but may increase taxpayers' welfare if they have paternalistic preferences and care more about preventing hunger than about the other aspirations of the poor. The PIs propose a rigorous experimental study to estimate (i) beneficiary preferences over equally-valued cash and in-kind transfers, (ii) the relative impact on nutrition of cash and in-kind transfers, and (iii) beneficiary valuation of in-kind benefits. This design allows one to measure both beneficiary preferences (using the take up rate) as well as the causal impact of cash vs. kind benefits on nutrition (using the random assignment of the offer to estimate both intent-to-treat and treatment-on-treated effects on nutrition). Further, the PIs offer additional randomly selected households the option to exchange their in-kind benefits for an experimentally varied cash transfer, which allows to estimate the demand for the status quo at various prices and to quantify the consumer surplus (or loss) beneficiaries obtain from in-kind benefits relative to cash transfers. Methodologically, the PIs integrate in one design the two paradigms that have dominated modern policy evaluation, one based on impacts, the other based on revealed preferences. In addition, by measuring take-up at randomly varied prices, the PIs are among the first to estimate individual-level beneficiary valuations of publicly-provided private goods using experimental data. The revealed preference approach is unique in enabling one to understand and accommodate heterogeneity of beneficiary preferences over cash and in-kind benefits, thereby reducing the political and ethical risks of policy experimentation in a critical area such as food security for the poor.