This paper derives optimal income tax formulas using compensated and uncompensated elasticities of earnings with respect to tax rates. A simple formula for the high income optimal tax rate is obtained as a function of these elasticities and the thickness of the top tail of the income distribution. In the general non-linear income tax problem, this method using elasticities shows precisely how the different economic effects come into play and which are the key relevant parameters in the optimal income tax formulas of Mirrlees. The optimal non-linear tax rate formulas are expressed in terms of elasticities and the shape of the income distribution. These formulas are implemented numerically using empirical earning distributions and a range of realistic elasticity parameters.

This paper investigates the optimal income transfer problem at the low end of the income distribution. The government maximizes a social welfare function and faces the traditional equity-efficiency trade-off. The paper models labor supply behavioral responses along the intensive margin (hours or intensity of work on the job) and along the extensive margin (participation in the labor force). Optimal tax formulas are derived as a function of the behavioral elasticities, the shape of the income distribution and the redistribution tastes of the government. When behavioral responses are concentrated along the intensive margin, the optimal transfer program is a classical Negative Income Tax program with a substantial guaranteed income support that is taxed away at high rates. However, when behavioral responses are concentrated along the extensive margin, the optimal transfer program is an Earned Income Credit program with negative marginal tax rates at low income levels and a small guaranteed income. Numerical simulations calibrated with the actual empirical earnings distribution are presented for a range of behavioral elasticities and redistributive tastes of the government. For realistic elasticities, the optimal program provides a moderate guaranteed income, imposes low tax rates on very low annual earnings levels, and then starts phasing out

This paper analyzes a randomized experiment to shed light on the role of information and social interactions in employees' decisions to enroll in a Tax Deferred Account (TDA) retirement plan within a large university. The experiment encouraged a random sample of employees in a subset of departments to attend a benefits information fair organized by the university, by promising a monetary reward for attendance. The experiment multiplied by more than five the attendance rate of these treated individuals (relative to controls), and tripled that of untreated individuals within departments where some individuals were treated. TDA enrollment five and eleven months after the fair was significantly higher in departments where some individuals were treated than in departments where nobody was treated. However, the effect on TDA enrollment is almost as large for individuals in treated departments who did not receive the encouragement as for those who did. We provide three interpretations—differential treatment effects, social network effects, and motivational reward effects—to account for these results.

This paper analyzes the effects of dividend taxation on corporate behavior using the large tax cut on individual dividend income enacted in 2003. We document a 20 percent increase in dividend payments by nonfinancial, nonutility publicly traded corporations following the tax cut. An unusually large number of firms initiated or increased regular dividend payments in the year after the reform. As a result, the number of firms paying dividends began to increase in 2003 after a continuous decline for more than two decades. Firms with high levels of nontaxable institutional ownership did not change payout policies, supporting the causality of the tax cut in increasing aggregate dividend payments. The response to the tax cut was strongest in firms with strong principals whose tax incentives changed (those with large taxable institutional owners or independent directors with large share holdings), and in firms where agents had stronger incentives to respond (high share ownership and low options ownership among top executives). Hence, principal-agent issues appear to play an important role in corporate responses to taxation.

This paper presents new homogeneous series on top shares of income and wages from 1913 to 1998 in the United States using individual tax returns data. Top income and wages shares display a U-shaped pattern over the century. Our series suggest that the large shocks that capital owners experienced during the Great Depression and World War II have had a permanent effect on top capital incomes. We argue that steep progressive income and estate taxation may have prevented large fortunes from fully recovering from these shocks. Top wage shares were flat before World War II, dropped precipitously during the war, and did not start to recover before the late 1960s but are now higher than before World War II. As a result, the working rich have replaced the rentiers at the top of the income distribution.

This paper analyzes the response of earnings to payroll tax rates using a cohort-based reform in Greece. All individuals who started working on or after 1993 face permanently a much higher earnings cap for payroll taxes, creating a large and permanent discontinuity in marginal payroll tax rates by date of entry in the labor force for upper earnings workers. Using full population administrative Social Security data and a Regression Discontinuity Design, we estimate the long-term incidence and effects of marginal payroll tax rates on earnings. Standard theory predicts that, in the long run, new regime workers should bear the entire burden of the payroll tax increase (relative to old regime workers). In contrast, we find that employers compensate new regime workers for the extra employer payroll taxes but not for the extra employee payroll taxes. We do not find any evidence of labor supply responses around the discontinuity, suggesting low efficiency costs of payroll taxes. The non-standard incidence results are the same across firms of different sizes. Tax incidence, however, is standard for older workers in the new regime as they bear both the employee and employer tax. Those results, combined with a direct small survey of employers, can be explained by social norms regarding seniority-based pay which create a growing wedge between pay and productivity as workers age.

We analyze a randomized experiment in which 14,000 tax filers in H&R Block offices in St. Louis received matches of zero, 20 percent, or 50 percent of IRA contributions. Take-up rates were 3 percent, 8 percent, and 14 percent, respectively. Among contributors, contributions, excluding the match, averaged $765 in the control group and $1100 in the match groups. Taxpayer responses to similar incentives in the Saver's Credit are much smaller. Taxpayers did not game the experiment by receiving a match and strategically withdrawing funds. Tax professionals significantly influenced contribution choices. These results suggest that both incentives and information affect behavior.

In Project STAR, 11,571 students in Tennessee and their teachers were randomly assigned to classrooms within their schools from kindergarten to third grade. This article evaluates the long-term impacts of STAR by linking the experimental data to administrative records. We first demonstrate that kindergarten test scores are highly correlated with outcomes such as earnings at age 27, college attendance, home ownership, and retirement savings. We then document four sets of experimental impacts. First, students in small classes are significantly more likely to attend college and exhibit improvements on other outcomes. Class size does not have a significant effect on earnings at age 27, but this effect is imprecisely estimated. Second, students who had a more experienced teacher in kindergarten have higher earnings. Third, an analysis of variance reveals significant classroom effects on earnings. Students who were randomly assigned to higher quality classrooms in grades K–3—as measured by classmates' end-of-class test scores—have higher earnings, college attendance rates, and other outcomes. Finally, the effects of class quality fade out on test scores in later grades, but gains in noncognitive measures persist.