Knowledge that Transforms

In a model with multiple Pareto-ranked equilibria, we show that the set of equilibria shrinks if we allow trade in assets that pay based on the realization of a sunspot acting as an equilibrium-selection device. When the probability of a low-output outcome is high, the desire to insure against it leads the poor to promise large transfers to the rich in the high-output state. The rich then lose the incentive to exert the effort needed to sustain the high output. Thus the opening of financial markets may destroy the high equilibrium.

This paper studies, theoretically and experimentally, the effects of overconfidence and fake news on information aggregation and the quality of democratic choice in a common-interest setting. We theoretically show that overconfidence exacerbates the adverse effects of widespread misinformation (i.e., fake news). We then analyze richer models that allow for partisanship, targeted misinformation intended to sway public opinion, and news signals correlated across voters (due to media ownership concentration or censorship). In our experiment, overconfidence severely undermines information aggregation, suggesting that the effect of overconfidence can be much more pronounced at the collective than at the individual level.

A data broker sells market segmentations to a producer with private cost who sells a product to a unit mass of consumers. This paper characterizes the revenue-maximizing mechanisms for the data broker. Every optimal mechanism induces quasi-perfect price discrimination. All the consumers with values above a cost-dependent cutoff buy by paying their values while the rest of consumers do not buy. The characterization implies that market outcomes remain unchanged even if the data broker becomes more powerful—either by gaining the ability to sell access to consumers or by becoming a retailer who purchases the product and sells to the consumers exclusively.

We study how political turnover in mayoral elections in Brazil affects public service provision by local governments. Exploiting a regression discontinuity design for close elections, we find that municipalities with a new party in office experience upheavals in the municipal bureaucracy: new personnel are appointed across multiple service sectors, and at both managerial and non-managerial levels. In education, the increase in the replacement rate of personnel in schools controlled by the municipal government is accompanied by test scores that are 0.05–0.08 standard deviations lower. In contrast, turnover of the mayor’s party does not impact local (non-municipal) schools. These findings suggest that political turnover can adversely affect the quality of public services when the bureaucracy is not shielded from the political process.

This paper identifies an upside of the separation of ownership and control, typically the source of inefficiencies in the theory of the firm. Because insiders obtain private information by exercising control, the separation of ownership and control leads to a separation of ownership and information. We show that this separation is necessary for efficient trade in the market for corporate control. The analysis reveals how strategic communication between inside and outside shareholders facilitates takeovers by eliciting external bidders’ private information. Our results call into question mandatory disclosure requirements during takeovers.

Health insurers increasingly compete on their networks of medical providers. Using data from Massachusetts’s insurance exchange, I find substantial adverse selection against plans covering the most prestigious and expensive “star” hospitals. I highlight a theoretically distinct selection channel: consumers loyal to star hospitals incur high spending, conditional on their medical state, because they use these hospitals’ expensive care. This implies heterogeneity in consumers’ incremental costs of gaining access to star hospitals, posing a challenge for standard selection policies. Along with selection on unobserved sickness, I find this creates strong incentives to exclude star hospitals, even with risk adjustment in place.

Workers' compensation insurance, which provides no-fault coverage for work-related injuries, is mandatory in nearly all states. We use administrative data from a unique market without a coverage mandate to estimate the demand for workers' compensation insurance, leveraging regulatory premium updates for identification. We find that a 1 percent increase in premiums leads to approximately a 0.3 percent decline in coverage. Drawing upon these estimates and data on costs, we examine potential justifications for government intervention to increase coverage. This analysis suggests that several forms of market failure-such as adverse selection, market power, and externalities-may not justify a mandate in this setting.

This paper examines the effects of the abandonment of China’s Grand Canal—the world’s largest and oldest artificial waterway—which served as a disruption to regional trade access. Using an original dataset covering 575 counties over 262 years, we show that the canal’s abandonment contributed to the social turmoil that engulfed North China in the nineteenth century. Counties along the canal experienced an additional 117 percent increase in rebelliousness after the canal’s closure relative to their non-canal counterparts. Our findings highlight the important role that continued access to trade routes plays in reducing conflict.