This paper examines the effects of taxation of human capital, physical capital and foreign assets in a multi-sector model of endogenous growth. It is shown that in general the growth rate is reduced by taxes on capital and labor (human capital) income. When the government faces no borrowing constraints and is able to commit to a given set of present and future taxes, it is shown that the optimal tax plan involves high taxation of both capital and labor in the short run. This allows the government to accumulate sufficient assets to finance spending without any recourse to distortionary taxation in the long run. When restrictions to government borrowing and lending are imposed, the model implies that human and physical capital should be taxed similarly.

In a second-best optimal growth setup with only factor taxes, it is in general optimal to fully replace capital by labor income taxation in the long run. We revisit this important issue by developing a human capital-based endogenous growth model with frictional labor search, allowing each firm to create multiple vacancies and each worker to determine market participation. We find that the conventional efficient bargaining condition is necessary but not sufficient for achieving constrained social optimality. We then conduct tax incidence exercises in balanced growth by calibrating to the U.S. economy with a pre-existing 20% flat tax on capital and labor income. Our quantitative results suggest that, due to a dominant channel via the interactions between vacancy creation and market participation, it is optimal to switch only partially from capital to labor taxation in a benchmark economy where human capital formation depends on both physical and human capital stocks. This main finding is robust even along the transition with time-varying factor tax rates. Moreover, our quantitative analysis under alternative setups suggest that while endogenous human capital and labor market frictions are essential for obtaining a positive optimal capital tax, endogenous leisure, nonlinear human capital accumulation and endogenous growth are not crucial.

This thesis consists of three chapters on optimal tax theory with endogenous wages. Chapter 1 studies optimal linear and nonlinear income taxation when firms do not know workers' abilities, and competitively screen them through nonlinear compensation contracts, unobservable to the government, in a Miyazaki-Wilson-Spence equilibrium. Adverse selection changes the optimal tax formulas because of the use of work hours as a screening tool, which for higher talent workers results in a "rat race," and for lower talent workers in informational rents and cross-subsidies. If the government has sufficiently strong redistributive goals, welfare is higher when there is adverse selection than when there is not. The model has practical implications for the interpretation, estimation, and use of taxable income elasticities, central to optimal tax design. Chapter 2 derives optimal income tax and human capital policies in a dynamic life cycle model with risky human capital formation through monetary expenses and training time. The government faces asymmetric information regarding the stochastic ability of agents and labor supply. When the wage elasticity with respect to ability is increasing in human capital, the optimal subsidy involves less than full deductibility of human capital expenses on the tax base, and falls with age. The optimal tax treatment of training time also depends on its interactions with contemporaneous and future labor supply. Income contingent loans, and a tax scheme with deferred deductibility of human capital expenses can implement the optimum. Numerical results suggest that full dynamic risk-adjusted deductibility of expenses is close to optimal, and that simple linear age-dependent policies can achieve most of the welfare gain from the second best. Chapter 3 considers dynamic optimal income, education, and bequest taxes in a Barro- Becker dynastic setup. Each generation is subject to idiosyncratic preference and productivity shocks. Parents can transfer resources to their children either through education investments, which improve the child's wage, or through financial bequests. I derive optimal linear tax formulas as functions of estimable sufficient statistics, robust to underlying heterogeneities in preferences. It is in general not optimal to make education expenses fully tax deductible. I also show how to derive equivalent formulas using reform-specific elasticities that can be targeted to already available estimates from existing reforms.

This paper examines the effects of taxation of human capital, physical capital and foreign assets in a multi-sector model of endogenous growth. It is shown that in general the growth rate is reduced by taxes on capital and labor (human capital) income. When the government faces no borrowing constraints and is able to commit to a given set of present and future taxes, it is shown that the optimal tax plan involves high taxation of both capital and labor in the short run. This allows the government to accumulate sufficient assets to finance spending without any recourse to distortionary taxation in the long run. When restrictions to government borrowing and lending are imposed, the model implies that human and physical capital should be taxed similarly.

The effects of income and consumption taxation are examined in the context of models in which the growth process is driven by the accumulation of human and physical capital. The different channels through which these taxes affect economic growth are discussed, and it is shown that in general the taxation of factor incomes (human and physical capital) is growth-reducing. The effects of consumption taxation on growth depend crucially on the elasticity of labor supply, and therefore on the specification of the leisure activity. The paper also derives implications for the optimal intertemporal choice of tax instruments.

Household and Economy: Welfare Economics of Endogenous Fertility deals with welfare economics and the socially optimal population size, as well as the social consequences of individual choice with respect to family size within each generation. The general equilibrium implications of endogenous fertility for a number of issues of population policy are discussed. In addition to their own consumption, the number of children and the utility of each child is assumed to enter the utility function of the parents. Comprised of 10 chapters, this volume begins with a review of social welfare criteria for optimal population size and the static theory of optimal population size, optimal population growth with exogenous fertility, and the theory of endogenous fertility. The reader is then introduced to the basic principles of welfare economics and the economics of externalities, followed by a summary of the traditional theory of household behavior. Subsequent chapters focus on optimal population size according to various social welfare criteria; real and potential externalities generated by the endogeneity of fertility; and the principal alternative reason for having children: to transfer resources from the present to support the future consumption of parents in old age. The book concludes by assessing the implications of endogenous fertility for within-generation income distribution policies and reflecting on the directions in which future research may be fruitful. This monograph will be of value to economists, social scientists, students of welfare economics, and those who wish to understand the contribution of economic analysis to an improved understanding of population policy.