Publications

Research Publications 

[Abstract]: While ``'Tis impossible to be sure of any thing but Death and Taxes" (Bullock, 1716), the structure of taxes and their burden have undergone large and frequent changes over time. We provide a brief history of U.S. federal income tax reforms since the 1960s, calculate effective federal income tax rates for each wave of the Panel Study of Income Dynamics, and discuss how effective taxation changed from 1969 to 2016. We show that most tax regimes are short-lived and that the variation in taxes over time and across groups is large. We also use an estimated dynamic model of couples and singles to show that the various tax regimes that we estimate imply very different labor market and saving behavior. These findings stress the importance of studying and modeling tax changes over time and across groups.

[Abstract]: In the U.S., both taxes and old age Social Security benefits depend on one's marital status and tend to discourage the labor supply of the secondary earner.  We study the effects of eliminating these marriage-related provisions on the labor supply and savings of two different cohorts. To do so, we estimate a rich life-cycle model of couples and singles using the Method of Simulated Moments (MSM) on the 1945 and 1955 birth-year cohorts. Our model matches well the life cycle profiles of labor market participation, hours, and savings for married and single people and generates plausible elasticities of labor supply. We find that these marriage-related provisions reduce the participation of married women over their life cycle, the participation of married men after age 55, and the savings of couples. These effects are large for both the 1945 and 1955 cohorts, even though the latter had much higher labor market participation of married women to start with.

[Abstract]: We document large differences between the United States and Europe in allocations of expenditures and time for both market and home activities. Using a life-cycle model with home production and endogenous retirement, we find that the cross-country differences in consumption tax, social security system, income tax, and TFP together can account for 68-95 percent of the cross country variations and more than half of the average differences between Europe and the United States in aggregate hours and expenditures. These factors can also account well for the cross-country differences in allocations by age and generate substantially lower market hours in Europe for the age group of sixty and above as in the data. All the factors, except income tax, are quantitatively important for determining cross-country differences in expenditure allocations. While the differences in social security system and income tax are crucial in explaining the difference in market hours around retirement ages, TFP and consumption tax are more important for the difference in market hours for prime ages.

 [Abstract]: To understand the link between financial intermediation activities and the real economy, we build a general equilibrium model in which agency frictions in the financial sector affect the efficiency of capital reallocation across firms and generate aggregate economic fluctuations. We develop a recursive policy iteration approach to fully characterize the nonlinear equilibrium dynamics and the off-steady-state crisis behavior. In our model, adverse shocks to agency frictions exacerbate capital misallocation and manifest themselves as variations in total factor productivity at the aggregate level. Our model endogenously generates countercyclical volatility in the aggregate time series and countercyclical dispersion in the marginal product of capital and asset returns in the cross section.

 [Abstract]: White, non-college-educated Americans born in the 1960s  face shorter life expectancies, higher medical expenses, and lower wages per unit of human capital compared with those born in the 1940s, and men's wages declined more than women's. After documenting these changes, we use a life-cycle model of couples and singles to evaluate their effects. The drop in wages depressed the labor supply of men and increased that of women, especially in married couples. Their shorter life expectancy reduced their retirement savings, but the increase in out-of-pocket medical expenses increased them by more. Welfare losses, measured as a onetime asset compensation, are 12.5%, 8%, and 7.2%  of the present discounted value of earnings for single men, couples, and single women, respectively. Lower wages explain 47%-58% of these losses, shorter life expectancies 25%-34%, and higher medical expenses account for the rest.

 [Abstract]: Wages, labor market participation, hours worked, and savings differ by gender and marital status. In addition, women and married people make up for a large fraction of the population and of labor market participants, total hours worked, and total earnings. For the most part, macroeconomists have been ignoring women and marriage in setting up structural models and by calibrating them using data on males only. In this paper we ask whether ignoring gender and marriage in both models and data implies that the resulting calibration matches well the key economic aggregates. We find that it does not and we ask  whether there are other calibration strategies or relatively simple models of marriage that can improve the fit of the model to aggregate data.

 [Abstract]: Piketty's book, Capital in the Twenty-First Century, discusses several factors affecting wealth inequality: rates of return on capital, output growth rates, tax progressivity, top income shares, and heterogeneity in saving rates and inheritances. This paper studies the role of various forces affecting savings in quantitative models of wealth inequality, discusses their successes and failures in accounting for the observed facts, and compares these model's implications with Piketty's conclusions. 

[Abstract]: We document the growth in higher education costs and tuition over the past 50 years. To explain these trends, we develop a general equilibrium model with skill- and sector-biased technical change. Finding the model’s parameters through a combination of estimation and calibration, we show that it can explain the rise in college costs between 1961 and 2009, along with the increase in college attainment and the change in the relative earnings of college graduates. The model predicts that if college costs had ceased to grow after 1961, enrollment in 2010 would be 3 to 6 percent higher.

[Abstract]: This paper generates two main contributions. First, it provides a new theory of wealth inequality that merges two empirically relevant forces generating inequality: bequest motives and inheritance of ability across generations; and an earnings process that allows for more earnings risk for the richest. Second, it uses the resulting calibrated framework to study the effects of changing estate taxation. Increasing the estate tax reduces the wealth concentration in the hands of the richest few and the economic advantage of being born to a rich and super-rich family at the cost of reduced aggregate capital and output. However, all of these effects are quite small. In contrast, increasing estate taxation can generate a significant welfare gain to a newborn under the veil of ignorance, but this comes at a large welfare cost for the super-rich. 

 [Abstract]: We test whether relative risk aversion varies with wealth using the Panel Study of Income Dynamics data. Our analytical results indicate that: (1) for each household, there are two channels through which the risky share responds to wealth fluctuations, the income channel and the habit channel; (2) across households, there are heterogeneous responses through the habit channel; and (3) two potential mis-identification problems arise when both heterogeneous responses through the habit channel and the responses through the income channel are ignored. Our empirical  findings show strong evidence of relative risk aversion varying with wealth after correcting two mis-identification problems.

 [Abstract]: We construct a model of optimal life-cycle housing and nonhousing consumption and estimate the elasticity between the two goods to be 0.487. The estimate is robust to different assumptions of housing adjustment cost, but sensitive to the choice of sample period and the degree of aggregation of data moments. We then conduct experiments in which house prices and household income fluctuate. Compared with the benchmark, the impact of the shocks on homeownership rates is reduced, but the impact on nonhousing consumption is magnified when housing service and nonhousing consumption are highly substitutable or when the house selling cost is sizable.

[Abstract]: This paper incorporates home production into a dynamic general equilibrium model of overlapping generations with endogenous retirement to study Social Security reforms. Specifically, home production takes housing, home input, and home hours as inputs and produces a good that is substitutable with market good. As such, the model differentiates both consumption goods and labor effort according to their respective roles in home production and market activities. Using a calibrated model, we conduct a policy experiment where we eliminate the current pay-as-you-go Social Security System. We find that the experiment has important implications for labor supply as well as consumption decisions and that these decisions are influenced by the presence of the home production technology. More importantly, comparing our economy to a one-good economy without home production, the welfare gains of eliminating Social Security are magnified significantly especially in the long run. The reasons are twofold and related to the general aspects of home production. First, home production implies a more elastic labor supply rendering the payroll labor tax more distortionary. Second, home production introduces insurance possibilities that are not present when only market-produced goods are available and, thus, reduces the need for government redistributive policies. 

[Abstract]: Households hold vastly heterogeneous amounts of wealth when they reach retirement, and differences in lifetime earnings explain only part of this variation. This paper studies the role of intergenerational transmission of ability, voluntary bequest motives, and the recipiency of accidental and intended bequests (both in terms of timing and size) in generating wealth dispersion at retirement, in the context of a rich quantitative model. Modeling voluntary bequests, and realistically calibrating them, not only generates more wealth dispersion at retirement and reduces the correlation between retirement wealth and lifetime income, but also generates a skewed bequest distribution that is close to the one in the observed data. 

[Abstract]: We incorporate home production in a dynamic general equilibrium model of consumption and savings with illiquid housing and a collateralized borrowing constraint. The calibrated model explains life-cycle patterns of household’s time use and consumption of different categories documented from the micro data. It predicts that the interaction of the labor efficiency profile and the home production technology explains household’s time use. The resulting income profiles, the endogenous borrowing constraint, and home production account for the initial hump in consumption. The complementarity of home hours, home input, and housing in home production drives the consumption profiles later in the life cycle. 

[Abstract]: This paper studies the long-run aggregate and welfare effects of eliminating Social Security in a quantitative dynamic general equilibrium life-cycle model where parents and their children are linked by voluntary and accidental bequests. Social Security in this model with impure altruism has a smaller effect on capital accumulation than in a pure life-cycle model, a bigger effect than in a model with two-sided altruism. The welfare gain of eliminating Social Security system under impure altruism is smaller than that in a pure life-cycle model, and bigger than that in a model with two-sided altruism.

[Abstract]: One striking phenomenon in the U.S. labor market is the reversal of the gender gap in college attainment. Females have outnumbered males in college attainment since 1987. We develop a discrete choice model of college entry decisions to study the driving forces of changes in college attainment by gender. We find that the increase in relative earnings between college-educated and high-school-educated individuals and the increasing parental education have important effects on the increase in college attainment for both genders but cannot explain the reversal of the gender gap. Rising divorce probabilities increase returns to college for females and decrease those for males, and thus are crucial in explaining the reversal of the gender gap in college attainment.

[Abstract]: Micro data over the life cycle show different patterns for consumption for housing and non-housing goods: The consumption profile of non-housing goods is hump-shaped, while the consumption profile for housing first increases monotonically and then flattens out. These patterns hold true at each consumption quartile. This paper develops a quantitative, dynamic, general equilibrium model of life-cycle behavior, that generates consumption profiles consistent with the observed data. Borrowing constraints are essential in explaining the accumulation of housing stock early in life, while transaction costs are crucial in generating the slow downsizing of the housing stock later in life.

  

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