We present an extrapolative model of bubbles. In the model, many investors form their demand for a risky asset by weighing two signals--an average of the asset's past price changes and the asset's degree of overvaluation. The two signals are in conflict, and investors "waver" over time in the...

Regulatory policies designed to improve societal welfare by "nudging" consumers to make better choices are increasingly popular. The application of benefit-cost analysis (BCA) to this sort of regulation confronts difficult theoretical and applied issues. In this analysis we contribute a worked...

Survey evidence suggests that many investors form beliefs about future stock market returns by extrapolating past returns: they expect the stock market to perform well (poorly) in the near future if it performed well (poorly) in the recent past. Such beliefs are hard to reconcile with existing...

Smoking is the leading preventable cause of death in the U.S. Because e-cigarettes do not involve the combustion of tobacco, vaping offers the potential to prevent most of the health consequences of smoking. We study the impact of an information shock created by an outbreak of lung injuries...