Heterogeneous Consumer Search and Social Learning: Empirical Studies

这两个研究项目探索了消费者需求的两个方面，它们可能对市场效率产生重要影响：异质消费者搜索和社交学习。这两个项目都使用了非常适合要解决的问题的新数据集。第一个项目考察了消费者在处方药零售市场上搜索的性质和强度。处方药的零售价格在不同药店之间差异很大，即使是在同一当地市场，之前的研究表明，价格差异的模式与消费者搜索的经济模型是一致的：例如，与一次性药物相比，重复购买的药物(购买价格的动机最强)的价格差异往往要小得多。该项目将调查两个小城市20多万份处方购买的数据。对于每笔交易，数据确定实际价格和支付类型(现金、第三方保险或医疗补助)以及处方特征。由于所有竞争对手的药店都有关于价格和数量的数据，有关消费者搜索范围的信息显示在观察到的市场份额对相对价格差异的敏感性中。这项研究将为有关价格差异和消费者搜索的重要问题提供答案：消费者在这些市场的搜索力度有多大(即，有多大比例的消费者选择在购买之前先定价购物？)不同药物之间的搜索强度差异是否与消费者搜索的经济学理论的预测一致？关于搜索成本的潜在分布，估计的搜索强度揭示了什么？第二个项目涉及社会学习对个人选择健康保险计划的影响。大公司的员工通常从雇主赞助的一系列健康保险选项中进行选择；由于选择健康计划可能是一个复杂的决定，个人可能会试图从同事那里了解计划的相对质量--要么通过直接沟通，要么通过基于观察到的选择得出推论。这种学习的原因和后果已经在理论文献中得到了形式化和讨论，但很少有人努力从经验上衡量社会学习的重要性。这项研究将使用一所主要大学的员工选择健康计划的数据，以获得对社会学习效果的定量估计。关于员工的人口统计信息--尤其是他们工作的部门--将被用来确定通过哪些沟通渠道进行学习。简单地说，如果个人在部门内的决策明显比跨部门的决策更相似，这可以被认为是一种学习或“羊群”效应的暗示。这是该项目主要方法背后的基本思想，即估计一个计量经济学模型，该模型结合了邻居的决定对个人决定的影响。实证结果将对学习的性质和程度、对需求分析和健康计划竞争的影响以及模仿行为造成的潜在福利损失的大小产生重要的见解。

This pair of research projects explores two aspects of consumer demand that can have important implications for market efficiency: heterogeneous consumer search and social learning. Both projects make use of new datasets that are uniquely well-suited for the questions to be addressed. The first project examines the nature and intensity of consumer search in retail markets for prescription drugs. Retail prices for prescription drugs vary widely across pharmacies even within the same local market, and previous research has shown that patterns in price dispersion are consistent with economic models of consumer search: for instance, prices tend to be much less disperse for medications that are purchased repeatedly (for which the incentives to price-shop are strongest) than for one-time medications. This project will investigate data on over 200,000 prescription purchases in two small cities. For each transaction, the data identify the actual price and payment type (cash, third-party insurance, or Medicaid) as well as prescription characteristics. Since data are available on prices and quantities at all competing pharmacies, information about the extent of consumer search is revealed in the observed sensitivity of market shares to relative price differences. The research will provide answers to important questions about price dispersion and consumer search: How intense is consumer search in these markets (i.e., what fraction of consumers chooses to price-shop before purchasing?) Is variation in search intensity across drugs consistent with the predictions of economic theories of consumer search? What do the estimated search intensities reveal about the underlying distribution of search costs? The second project concerns the impact of social learning on individuals' choices of health insurance plans. Employees of large firms typically choose from a set of health insurance options sponsored by their employer; since the choice of a health plan can be a complex decision, individuals may attempt to learn about plans' relative qualities from co-workers-either through direct communication or by drawing inferences based observed choices. The causes and consequences of this kind of learning have been formalized and discussed in the theoretical literature, but little effort has been made to measure the importance of social learning empirically. This study will use data on the health plan choices of the employees of a major university to obtain quantitative estimates of the effects of social learning. Information about employee demographics--and especially the departments in which they work-will be used in identifying the communication channels through which learning occurs. Stated very simply, if individuals' decisions are significantly more similar within departments than they are across departments, this can be taken as suggestive of a learning or "herding" effect. This is the basic idea underlying the project's principal approach, which is to estimate an econometric model of health plan choice that incorporates the influence of neighbors' decisions on the decision of the individual. The empirical results will yield important insights into the nature and extent of learning, the implications for demand analysis and health plan competition, and the magnitude of potential welfare losses due to imitative behavior.