Knowledge that Transforms

This paper finds households with children and elderly dependents, the “Sandwich Generation,” significantly reduce both college savings and stockholding. Having any elderly dependents decreases the probability of both stockholding and college savings by twice as much as poor personal health. Hence, these results have critical implications as they demonstrate the importance and magnitude of links between the pension system, college financial aid, and wealth accumulation. Elderly dependents limiting parental funds for offspring education can decrease offspring long-term earnings potential via decreased human capital accumulation. Furthermore, decreased stock holdings can decrease long-term wealth accumulation and thus intergenerational wealth transfers.

We consider a moral hazard problem where the principal is uncertain as to what the agent can and cannot do: she knows some actions available to the agent, but other, unknown actions may also exist. The principal demands robustness, evaluating possible contracts by their worst-case performance, over unknown actions the agent might potentially take. The model assumes risk-neutrality and limited liability, and no other functional form assumptions. Very generally, the optimal contract is linear. The model thus offers a new explanation for linear contracts in practice. It also introduces a flexible modeling approach for moral hazard under nonquantifiable uncertainty. (JEL D81, D82, D86)

We examine whether online learning technologies have led to lower prices in higher education. Using data from the Integrated Postsecondary Education Data System, we show that online education is concentrated in large for-profit chains and less-selective public institutions. We find that colleges with a higher share of online students charge lower tuition prices. We present evidence of declining real and relative prices for full-time undergraduate online education from 2006 to 2013. Although the pattern of results suggests some hope that online technology can “bend the cost curve” in higher education, the impact of online learning on education quality remains uncertain.

The optimal allocation of resources in complex environments—like allocation of dynamic wireless spectrum, cloud computing services, and Internet advertising—is computationally challenging even given the true preferences of the participants. In the theory and practice of optimization in complex environments, a wide variety of special and general purpose algorithms have been developed; these algorithms produce outcomes that are satisfactory but not generally optimal or incentive compatible. This paper develops a very simple approach for converting any, potentially non-optimal, algorithm for optimization given the true participant preferences, into a Bayesian incentive compatible mechanism that weakly improves social welfare and revenue. (JEL D82, H82, L82)

Piketty argues that r > g is the “the central contradiction of capitalism” and that it will lead to an “endless inegalitarian spiral.” As a result, he argues for a new global tax on capital. In this brief essay, I explain why I am not persuaded by either his prediction or his prescription.

Electricity and water are often subsidized in developing countries to increase their affordability for low-income households. Ideally, such subsidies would create sufficient demand in poor neighborhoods to encourage private investment in their infrastructure. Instead, many regions receiving large subsidies have precarious distribution networks supplying users who never pay. Using a structural model of household electricity demand in Colombia, I predict the change in consumption and profits from upgrading low-quality electricity connections. I show that the existing subsidies, which provide greater transfers to areas with unreliable supply, deter investment to modernize infrastructure. Finally, I analyze alternative programs with stronger investment incentives. (JEL H23, H54, L94, L98, O12, O13)

We analyze a notion of self-confirming equilibrium with non-neutral ambiguity attitudes that generalizes the traditional concept. We show that the set of equilibria expands as ambiguity aversion increases. The intuition is quite simple: by playing the same strategy in a stationary environment, an agent learns the implied distribution of payoffs, but alternative strategies yield payoffs with unknown distributions; increased aversion to ambiguity makes such strategies less appealing. In sum, a kind of “status quo bias” emerges; in the long run, the uncertainty related to tested strategies disappears, but the uncertainty implied by the untested ones does not. (JEL C72, C73, D81, D83)

Industrial organization studies the exercise and control of market power. To this purpose, it builds models that capture the essence of the situation. The predictions of the model can then be tested econometrically and possibly in the lab or the field. In the end, the reasonableness of, and robustness to modeling assumptions and the quality of empirical fit determine how confident economists are in making recommendations to public decision-makers for intervention, and to companies for the design of their business model. Industrial organization has a long tradition: first theoretical, with the work of French “engineer-economists” Antoine Augustin Cournot (1838) and Jules Dupuit (1844); then policy-oriented with the enactment of the Sherman Act (1890) and subsequent legislation; then descriptive with the studies of the Harvard school (“Structure-Conduct-Performance”) comforting and refining the antitrust drive; and finally skeptical with the Chicago school. The Chicago school correctly pointed out the lack of underlying theoretical doctrine and went on to cast doubt on the whole edifice. It however did not develop an alternative antitrust doctrine, perhaps because

The Affordable Care Act has engendered significant changes in the design of health insurance products. We examine the “narrowness” of hospital networks affiliated with plans offered in the first year of the marketplaces. Using data from Texas, we find limited evidence of a tight link between pricing and a simple measure of network breadth, or a more complex measure of network value derived from a logit model of hospital choice. The state's largest insurer priced its narrow networks at a fairly constant discount relative to its broad networks, notwithstanding significant variation in its broad-narrow gap across geographic markets in Texas.

Drug trade-related violence has escalated dramatically in Mexico since 2007, and recent years have also witnessed large-scale efforts to combat trafficking, spearheaded by Mexico's conservative PAN party. This study examines the direct and spillover effects of Mexican policy toward the drug trade. Regression discontinuity estimates show that drug-related violence increases substantially after close elections of PAN mayors. Empirical evidence suggests that the violence reflects rival traffickers' attempts to usurp territories after crackdowns have weakened incumbent criminals. Moreover, the study uses a network model of trafficking routes to show that PAN victories divert drug traffic, increasing violence along alternative drug routes. (JEL D72, D85, K42, O17, Z13)