Efficient Sorting in a Dynamic Adverse-Selection Model

We discuss a class of markets for durable goods where efficiency (or approximate efficiency) is obtained despite the presence of information asymmetries. In the model, the number of times a good has changed hands (the vintage of the good) is an accurate signal of its quality, each consumer self-selects into obtaining the vintage that the social planner would have assigned to her, and consumers' equilibrium trading behaviour in secondary markets is not subject to adverse selection. We show that producers have the incentive to choose contracts that lead to the efficient allocation, and to supply the efficient output. We also provide a contrast between leasing contracts, resale contracts, and different kinds of rental contracts. Resale contracts do not lead to the efficient allocation. A specific kind of rental contract provides the appropriate incentives to consumers.     

Asymmetric information in health insurance: evidence from the National Medical Expenditure Survey.

Adverse selection is perceived to be a major source of market failure in insurance markets. There is little empirical evidence on the extent of the problem. We estimate a structural model of health insurance and health care choices using data on single individuals from the NMES. A robust prediction of adverse-selection models is that riskier types buy more coverage and, on average, end up using more care. We test for unobservables linking health insurance status and health care consumption. We find no evidence of informational asymmetries.     

Estimating Multiple-Discrete Choice Models: An Application to Computerization Returns

Buyers in many markets face multiple-discrete choices: they can purchase multiple-units as well as multiple-brands at the same time. This paper presents a multiple-discrete choice model for the analysis of differentiated products demand. Users maximize profits by choosing the number of units of each brand they purchase. I estimate the model using micro-level data on the demand for personal computers. I use the estimated demand structure to assess the welfare gains from computerization and technological innovation in peripherals. The estimated return on investment in personal computers is 92%. Moreover, a 10% increase in the performance-to-price ratio of microprocessors leads to a 2·2% gain in the estimated user surplus.     

Sales and consumer inventory

Temporary price reductions (sales) are common for many goods and naturally result in a large increase in the quantity sold. We explore whether the data support the hypothesis that these increases are, at least partly, due to demand anticipation: at low prices, consumers store for future consumption. This effect, if present, has broad economic implications. We test the predictions of an inventory model using scanner data with two years of household purchases. The results are consistent with an inventory model and suggest that static demand estimates may overestimate price sensitivity.     

The Post-Promotion Dip Puzzle: What do the Data Have to Say?

One of the puzzles of store-level scanner data is the lack of a dip in quantity sold in the weeks following a promotion. Such a dip is predicted by a consumer inventory model. During a promotion consumers buy more, not only for current consumption, but stockpile for future consumption. The predictions of such a model have been confirmed by household-level data yet seem harder to find in aggregate brand- or category-level data. We re-examine this puzzle and reach two conclusions. First, the effects at the household-level are present, but are much smaller than previously found. Our estimates are different because we control for household heterogeneity in a more general way than most previous work. This suggests that since the effects are small they might be harder to spot in aggregate data. Second, we show that the dip is present in the aggregate data, once we control for additional promotional activity, like feature and display. The latter has an opposing dynamic effect that masks the existence of the post-promotion dip.     

Consumers' activism: the cottage cheese boycott

We study a consumer boycott on cottage cheese, organized in Israel on Facebook in the summer of 2011 following a steep price increase since 2006. The boycott led to an immediate decline in prices, which remain low even six years later. We find that (i) demand at the start of the boycott would have been 30% higher but for the boycott, (ii) own‐ and especially cross‐price elasticities increased substantially after the boycott, and (iii) post‐boycott prices are substantially below the levels implied by the post‐boycott demand elasticities, suggesting that firms were concerned with public backlash due to high prices.