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Publications

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Discussion Paper
Abstract

Reclassification risk is a major concern in health insurance where contracts are typically one year in length but health shocks often persist for much longer. While most health systems with private insurers emphasize short-run contracts paired with substantial pricing regulations to reduce reclassification risk, long-term contracts with one-sided insurer commitment have significant potential to reduce reclassification risk without the negative side effects of price regulation, such as adverse selection. In this paper, we theoretically characterize optimal long-term insurance contracts with one-sided commitment, extending prior models of this form in several key directions that are important for studying health insurance markets. We leverage this characterization to provide a simple algorithm for computing optimal contracts from primitives. We estimate key market fundamentals using data on all under-65 privately insured consumers in Utah and pair these estimates with our model to study comparative statics related to contract design and welfare. We find that the welfare value of a system that effectively implements these long-term contracts depends crucially on (i) the degree of public insurance pre-system health risk (ii) the distribution of expected lifetime income gradients in the population (iii) the stochastic process governing life-cycle health shocks (iv) the extent of consumer switching costs and (v) the degree of consumer myopia.

Discussion Paper
Abstract

Using a lifecycle model of consumption, saving and portfolio choice combined with linked survey and administrative data on wealth and lifetime earnings we evaluate measures of retirement preparedness. We estimate heterogeneous discount factors for households and compare the estimates of their patience to their replacement rates { the simple measure of- ten used to evaluate the adequacy of retirement savings. We find first that the specification of the model’s asset structure matters quantitatively for preference parameter estimates { households appear to be much more patient when they are assumed to have access only to a risk-free asset compared to when we account for the fact that much of their wealth is stored in higher-return tax-advantaged private pensions and in housing. Second we find that only the most patient households achieve the replacement rates out of final earnings that are often recommended by policy-makers and industry as sensible benchmarks for retirement preparedness. Notwithstanding this, we find that even quite impatient households in the population we study achieve high replacement rates out of lifetime average income { a more sensible summary measure of preparedness for retirement.

Discussion Paper
Abstract

This paper studies the e ects of economies of density in transportation markets, focusing on ridesharing. Our theoretical model predicts that (i) economies of density skew the supply of drivers away from less dense regions, (ii) the skew will be more pronounced for smaller platforms, and (iii) rideshare platforms do not nd this skew ecient and thus use prices and wages to mitigate (but not eliminate) it. We then develop a general empirical strategy with simple implementation and limited data requirements to test for spatial skew of supply from demand. Applying our method to ride-level, multi-platform data from New York City (NYC), we indeed nd evidence for a skew of supply toward busier areas, especially for smaller platforms. We discuss the implications of our analysis for business strategy (e.g., surge pricing) and public policy (e.g., consequences of breaking up or downsizing a rideshare platform).

Discussion Paper
Abstract

Socialism is back on the political agenda in the United States. Politicians and some economists who identify as socialists, however, do not discuss property relations, a topic that was central in the intellectual history of socialism, but rather limit themselves to advocacy of economic reforms, funded through taxation, that would tilt the income distribution in favor of the disadvantaged in society. In the absence of a more precise discussion of property relations, the presumption must be that ownership of firms would remain private or corporate with privately owned shares. This formula is identified with the Nordic and other western European social democracies.

In this article, I propose several variants of socialism, which are characterized by different kinds of property relation in the ownership of society’s firms. In addition to varying property relations, I include as part of socialism a conception of what it means for a socialist society to possess a cooperative ethos, in place of the individualistic ethos of capitalist society. Differences in ethea are modeled as differences in the manner in which economic agents optimize. With an individualistic ethos, economic agents optimize in the manner of John Nash, while under a cooperative ethos, many optimize in the manner of Immanuel Kant. It is shown that Kantian optimization can decentralize resource allocation in ways that neatly separate issues of income distribution from those of efficiency. In particular, remuneration of labor and capital contributions to production need no longer be linked to marginal-product pricing of these factors, as is the key to efficiency with capitalist property relations. I present simulations of socialist income distributions, and offer some tentative conclusions concerning how we should conceive of socialism today.

Discussion Paper
Abstract

Reclassification risk is a major concern in health insurance where contracts are typically one year in length but health shocks often persist for much longer. We use rich individual-level medical information from the Utah all-payer claims database to empirically study one possible solution: long-term insurance contracts. We characterize optimal long-term contracts with one-sided commitment theoretically, derive the contracts that are optimal for consumers in Utah, and assess the welfare level that a full implementation of these contracts could achieve relative to several key benchmarks. We find that dynamic contracts perform very well for the majority of the population, for example, eliminating over 94% of the welfare loss from reclassification risk for individuals who arrive on the market at age 25 in good health. However, dynamic contracts instead provide very little benefit to the worst pre-age-25 health risks. Their value is also substantially lower for consumers whose income growth with age is relatively high. With pre-age-25 insurance in place, consumers with flat net income prefer dynamic contracts to an ACA-like environment, but consumers with steeper income profiles prefer the ACA-like environment. Overall, we show that there are scenarios in which dynamic contracts can provide substantial welfare benefits, but that complementary policies are crucial for unlocking these benefits.

Discussion Paper
Abstract

We examine two-sided markets where players arrive stochastically over time and are drawn from a continuum of types. The cost of matching a client and provider varies, so a social planner is faced with two contending objectives: a) to reduce players’ waiting time before getting matched; and b) to form efficient pairs in order to reduce matching costs. We show that such markets are characterized by a quick or cheap dilemma: Under a large class of distributional assumptions, there is no `free lunch’, i.e., there exists no clearing schedule that is simultaneously optimal along both objectives. We further identify a unique breaking point signifying a stark reduction in matching cost contrasted by an increase in waiting time. Generalizing this model, we identify two regimes: one, where no free lunch exists; the other, where a window of opportunity opens to achieve a free lunch. Remarkably, greedy scheduling is never optimal in this setting.