We use data from eBay to identify hundreds of thousands of instances in which retailers posted otherwise identical product listings with targeted variation in pricing and auction design. We use these matched listings to measure the dispersion in auction prices for identical goods sold by the...

We present a simple graphical framework to illustrate the potential welfare gains from a “top-up” health insurance policy requiring patients to pay the incremental price for more expensive treatment options. We apply this framework to breast cancer treatments, where lumpectomy with radiation...

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...

We estimate the sensitivity of Internet retail purchasing to sales taxes using data from the eBay marketplace. Our first approach exploits the fact that seller locations are revealed only after buyers have expressed interest in an item by clicking on its listing. We use millions of location...

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 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...

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 use employee-level panel data from a single firm to explore the possibility that individuals may select insurance coverage in part based on their anticipated behavioral ("moral hazard") response to insurance, a phenomenon we label "selection on moral hazard." Using a model of plan choice and...

We estimate the sensitivity of Internet retail purchasing to sales taxes using eBay data. Our first approach exploits the fact that a seller's location?and therefore the applicable tax rate?is revealed only after a buyer has expressed interest in an item. We document how adverse tax "surprises"...