We use a detailed micro dataset on product availability to construct a direct high-frequency measure of consumer product shortages during the 2020-2021 pandemic. We document a widespread multi-fold rise in shortages in nearly all sectors early in the pandemic. Over time, the composition of...

Hoarding of staples has long worried policymakers due to concerns about shortages. We quantify how sticky store prices---delayed price adjustment to shocks by reputable retailers---exacerbate hoarding. When prices are sticky, households hoard not only for precautionary motives but also...

Climate modelers have recognized the possibility of abrupt climate changes caused by a reorganization of the North Atlantic's current pattern (technically known as a thermohaline circulation collapse). This circulation system now warms north-western Europe and transports carbon dioxide to the...

We study a model of retrospective search in which an agent--a researcher, an online shopper, or a politician--tracks the value of a product. Discoveries beget discoveries and their observations are correlated over time, which we model using a Brownian motion. The agent, a standard exponential...

We propose a new method for solving high-dimensional dynamic programming problems and recursive competitive equilibria with a large (but finite) number of heterogeneous agents using deep learning. The "curse of dimensionality" is avoided due to four complementary techniques: (1) exploiting...

We study the optimal pattern of outlays for a single firm pursuing an R&D program over time. In the deterministic case, (a) the amount of progress required to complete the project is known, and (b) the relationship between outlays and progress is known. In this case, it is optimal to increase...

This paper shows how to build algorithms that use graphics processing units (GPUs) installed in most modern computers to solve dynamic equilibrium models in economics. In particular, we rely on the compute unified device architecture (CUDA) of NVIDIA GPUs. We illustrate the power of the approach...

We examine whether unregulated, private insurance markets efficiently provide insurance against reclassification risk (the risk of becoming a bad risk and facing higher premiums). To do so, we examine the ex-post risk type of individuals who drop their long-term care insurance contracts relative...

"Buffer-stock" versions of the dynamic stochastic optimizing model of saving are now standard in the consumption literature. This paper builds theoretical foundations for rigorous understanding of the main characteristics of buffer stock models, including the existence of a target level of...