We report results from a validation study of Nielsen Homescan data. We use data from a large grocery chain to match thousands of individual transactions that were recorded by both the retailer (at the store) and the Nielsen Homescan panelist (athome). First, we report how often shopping trips...

We present a graphical framework for analyzing both theoretical and empirical work on selection in insurance markets. We begin by using this framework to review the "textbook" adverse selection environment and its implications for insurance allocation, social welfare, and public policy. We then...

Government intervention in insurance markets is ubiquitous and the theoretical basis for such intervention, based on classic work from the 1970s, has been the problem of adverse selection. Over the last decade, empirical work on selection in insurance markets has gained considerable momentum....

We re-present and re-examine the analysis from the famous RAND Health Insurance Experiment from the 1970s on the impact of consumer cost sharing in health insurance on medical spending. We begin by summarizing the experiment and its core findings in a manner that would be standard in the current...

Search frictions can explain why the "law of one price" fails in retail markets and why even firms selling commodity products have pricing power. In online commerce, physical search costs are low, yet price dispersion is common. We use browsing data from eBay to estimate a model of consumer...

We estimate the economic surplus created by Medicare Advantage under its reformed competitive bidding rules. We use data on the universe of Medicare beneficiaries, and develop a model of plan bidding that accounts for both market power and risk selection. We find that private plans have costs...

International tourism is a fast growing industry generating half a trillion dollars in annual revenues and accounting for almost 10% of total international trade, and almost half of total trade in services. Yet, it has so far failed to receive the attention it deserves from mainstream economics....

Empirical studies find substantial differences in demand elasticities and associated markups among products of different quality. This paper analyzes the theoretical determinants of such variation. We present a simple model that allows for horizontal and vertical differentiation and accounts for...

We estimate the economic surplus created by Medicare Advantage under its reformed competitive bidding rules. We use data on the universe of Medicare beneficiaries, and develop a model of plan bidding that accounts for both market power and risk selection. We find that private plans have costs...

We present new evidence on consumer liquidity constraints and the credit market conditions that might give rise to them. Our analysis is based on unique data from a large auto sales and financing company that serves the subprime market. We first document the role of short-term liquidity in...