This paper provides empirically implementable sufficient statistics formulas for optimal nonlinear tax systems in the presence of across-income heterogeneity in preferences, inheritances, income-shifting capabilities, and other sources. We characterize optimal smooth tax systems on income and savings (or other commodities), as well as simpler tax systems. We use familiar elasticity concepts and a novel sufficient statistic for heterogeneity correlated with earnings ability: the difference between across-income variation in savings and the causal effect of income on savings. We apply these formulas to the United States and find that the optimal savings tax is mostly positive and progressive.

We use public finance sufficient statistic approaches to characterize the welfare effects of “nudges,” such as simplified information and warning labels, in markets with taxes and endogenous prices. While many studies focus on average effects, we show that welfare also depends on how the nudge affects the variance of choice distortions, and average effects become irrelevant with zero pass-through or optimal taxes. We implement the framework with experiments evaluating automotive fuel economy labels and sugary drink health labels. Labels decrease purchases of low-fuel economy cars and sugary drinks but may decrease welfare because they increase the variance of choice distortions.

Public recognition is frequently used to motivate desirable behavior, yet its welfare effects—such as costs of shame or gains from pride— are rarely measured. We develop a portable empirical methodology for measuring and monetizing social image utility, and we deploy it in experiments on exercise and charitable behavior. In all experiments, public recognition motivates desirable behavior but creates highly unequal image payoffs. High-performing individuals enjoy significant utility gains, while low-performing individuals incur significant utility losses. We estimate structural models of social signaling, and we use the models to explore the social efficiency of public recognition policies.

This article investigates whether offers of commitment contracts, in the form of self-imposed choice-set restrictions and penalties with no financial upside, are well-targeted tools for addressing self-control problems. In an experiment on gym attendance (N=1,248), we examine take-up of commitment contracts and also introduce a separate elicitation task to identify actual and perceived time inconsistency. There is high take-up of commitment contracts for greater gym attendance, resulting in significant increases in exercise. However, this take-up is influenced both by noisy valuation and incorrect beliefs about one’s time inconsistency. Approximately half of the people who take up commitment contracts for higher gym attendance also take up commitment contracts for lower gym attendance. There is little association between commitment contract take-up and reduced-form and structural estimates of actual or perceived time inconsistency. A novel information treatment providing an exogenous shock to awareness of time inconsistency reduces demand for commitment contracts. Structural estimates of a model of quasi-hyperbolic discounting and gym attendance imply that offering our commitment contracts lowers consumer surplus and is less socially efficient than utilizing linear exercise subsidies that achieve the same average change in behaviour.

This paper develops and deploys a methodology for testing whether people correctly value tools that reduce attention costs. We call these tools bandwidth enhancements (BEs) and characterize how demand for BEs varies with the pecuniary incentives to be attentive, under the null hypothesis of correct perceptions and optimal choice. We examine if the theoretical optimality conditions are satisfied in three experiments. The first is a field experiment ( n = 1373) with an online education platform, in which we randomize incentives to complete course modules and incentives to utilize a plan‐making tool to complete the modules. In the second experiment ( n = 2306), participants must complete a survey in the future. We randomize survey‐completion incentives and how long participants must wait to complete the survey, and we elicit willingness to pay for reminders. The third experiment ( n = 1465) involves a psychometric task in which participants must identify whether there are more correct or incorrect mathematical equations in an image. We vary incentives for accuracy, elicit willingness to pay to reduce task difficulty, and examine the impact of learning and feedback. In all experiments, demand for reducing attention costs increases as incentives for accurate task completion increase. However, in all experiments—and across all conditions—our tests imply that this increase in demand is too small relative to the null of correct perceptions. These results suggest that people may be uncertain or systematically biased about their attention cost functions, and that experience and feedback do not necessarily eliminate bias.