We study a market with free entry and exit of firms who can produce high-quality output by making a costly but efficient initial unobservable investment. If no learning about this investment occurs, an extreme "lemons problem" develops, no firm invests, and the market shuts down. Learning...

The CDC reports that 1.13 million Americans have died of COVID-19 through June of 2023. I use a model of the impact over the past three years of vaccines and private and public behavior to mitigate disease transmission during the COVID-19 pandemic in the United States to address two questions....