This paper analyzes the effects of the lower bound for interest rates on the distributions of inflation and interest rates. In a New Keynesian model with a lower bound, two equilibria emerge: policy is mostly unconstrained in the “target equilibrium,” whereas policy is mostly constrained in the “liquidity trap equilibrium.” Using options data on interest rates and inflation, we find forecast densities consistent with the target equilibrium and find no evidence in favor of the liquidity trap equilibrium. The lower bound has a sizable effect on the distribution of interest rates, but its impact on inflation is relatively modest.

Allocating appointment slots is presented as a new application for market design. Online booking systems are commonly used by public authorities to allocate appointments for visa interviews, driver’s licenses, passport renewals, etc. We document that black markets for appointments have developed in many parts of the world. Scalpers book the appointments that are offered for free and sell the slots to appointment seekers. We model the existing first-come-first-served booking system and propose an alternative batch system. The batch system collects applications for slots over a certain time period and then randomly allocates slots to applicants. The theory predicts and lab experiments confirm that scalpers profitably book and sell slots under the current system with sufficiently high demand, but that they are not active in the proposed batch system. We discuss practical issues for the implementation of the batch system and its applicability to other markets with scalping.

We study a repeated game of price leadership in which a firm proposes supermarkups over Bertrand prices to a coalition of rivals. Supermarkups and marginal costs are recoverable from data on prices and quantities using the model’s structure. In an application to the beer industry, we find that price leadership increases profit relative to Bertrand competition by 17 percent in fiscal years 2006 and 2007, and by 22 percent in 2010 and 2011, with the change mostly due to consolidation. We simulate two mergers, which relax binding incentive compatibility constraints and increase supermarkups. These coordinated effects arise even with efficiencies that offset price increases under Bertrand competition.

We study reforms of nonlinear income tax systems from a political economy perspective. We present a median voter theorem for monotonic tax reforms, reforms so that the change in the tax burden is a monotonic function of income. We also provide an empirical analysis of tax reforms, with a focus on the United States. We show that past reforms have, by and large, been monotonic. We also show that support by the median voter was aligned with majority support in the population. Finally, we develop sufficient statistics that enable to test whether a given tax system admits a politically feasible reform.

How do foreign powers disengage from a conflict? We study this issue by examining the recent, large-scale security transition from international troops to local forces in the ongoing civil conflict in Afghanistan. We construct a new dataset that combines information on this transition process with declassified conflict outcomes and previously unreleased quarterly survey data of residents’ perceptions of local security. Our empirical design leverages the staggered roll-out of the transition, and employs a novel instrumental variables approach to estimate the impact. We find a significant, sharp, and timely decline of insurgent violence in the initial phase: the security transfer to Afghan forces. We find that this is followed by a significant surge in violence in the second phase: the actual physical withdrawal of foreign troops. We argue that this pattern is consistent with a signaling model, in which the insurgents reduce violence strategically to facilitate the foreign military withdrawal to capitalize on the reduced foreign military presence afterward. Our findings clarify the destabilizing consequences of withdrawal in one of the costliest conflicts in modern history, and yield potentially actionable insights for designing future security transitions.