A Multiplicative Model of Investment in Human Capital

The purpose of this paper is to analyze the effects of changes in exogenous parameters such as the interest rate, the length of the working period and initial endowments on the shape of the observed earnings profile. Though this problem can be treated in general, we shall restrict ourselves to the following "inverse optimal" problem: find a form of the trade-off function between current and future earnings which leads to a logarithmic earnings function. In the paper we demonstrate that logarithmic earning functions can be derived from optimal behavior. Specifically, the simple case which we analyze leads to piece wise linear log earnings functions. Such a derivation has the advantage that the effects on earnings of exogenous factors can be consistently analyzed. The model is sufficiently simple to allow a clear exposition of the basic elements which govern earnings in a static world. The same elements appear in the more complicated derivations currently available in the literature but it is more difficult to trace their impact. The multiplicative model provides additional information on the robustness of the results previously derived from the Ben-Porath specification. This is particularly important since the "production function" for human capital is not directly observable and alternative specification can only be compared in terms of their implications with respect to observed earnings.

The Wealth Effect in Occupational Choice

The purpose of this paper is to indicate regularities in the area of occupational choice using income-leisure analysis. A simple one-period model is used to examine the effect of changes in nonhuman and human wealth on the choice of an occupation. It is argued that under certainty: An increase in nonwage income will increase the propensity to choose pleasant low-paying work activities. An increase in human capital will also induce a choice of pleasant work activities if the income effect is dominant. Under conditions of uncertainty an increase in nonwage income will tend to encourage the choice of risky high-paying work activities if their monetary returns are uncertain. If the nonmonetary returns of an occupation are uncertain the propensity to choose it will tend to decrease with wealth. Finally, an increase in human capital is likely to discourage the choice of occupations with risky monetary returns.

Expected Interruptions in Labor Force Participation and Sex Related Differences in Earnings Growth

The paper analyzes the joint determination of wives' earnings and labor force participation over the life cycle given the interruptions in wives' work careers. The interruptions affect the profitability of the investment in human capital, which in turn determines earnings. The earnings prospects feed back into the participation decision, namely, the decision whether and for how long to drop out of the labor force. The formal analysis compares the age-earnings profiles of persons who drop out of the labor force with those who do not during the pre- and post-interruption period. The comparison is carried out where interruptions are assumed to be exogenous and when they are endogenous. The effect of productivity at home, the initial stock of human capital and its rental value on the length of the interruption is investigated.

Inequality Within and Between Families

Between-family differences in expenditures and output reflect the effect of simultaneous increases in children's ability on the willingness of parents to transfer resources to them. Within-family differences also reflect the attitudes of parents toward disparity among children. In this paper we characterize the conditions on parents' preferences that determine whether between-family differences exceed within-family differences. For an additive utility, within-family differences in expenditures always exceed between-family differences. This may also be true for the maximum utility function if an increase in ability reduces the marginal utility of income. Within-family differences in output (utility or income) can also exceed between-family differences. In this case, the implication for income distribution is that equality is enhanced by a higher correlation of ability between brothers.

Return Migration: Theory and Empirical Evidence

In this paper we discuss forms of migration that are non-permanent. We focus on temporary migrations where the decision to return is taken by the immigrant. These migrations are likely to be frequent, and we provide some evidence for the UK. We then develop a simple model which rationalizes the decision of a migrant to return to his home country, despite a persistently higher wage in the host country. We consider three motives for a temporary migration: Differences in relative prices in host- and home country, complementarities between consumption and the location where consumption takes place, and the possibility of accumulating human capital abroad which enhances the immigrant's earnings potential back home. For the last return motive, we discuss extensions which allow for immigrant heterogeneity, and develop implications for selective in- and out- migration.Life Cycle Models, International Migration, Return Migration

Experience, Vintage and Time Effects in the Growth of Earnings: AmericanScientists, 1960-1970

This paper is concerned with the growth of individual earnings over time. Four aspects of time are distinguished: experience, age, vintage and calendar year. The first section of the paper provides a brief outline of a theory of planned growth in earnings. The second and main section of the paper is devoted to an empirical attempt to estimate the role of experience, vintage and age on the growth in earnings and to separate these effects from exogenous changes in market conditions. We present a detailed specification of the earnings function which accounts for the inherent multi-collinearity between variables such as time, vintage and experience. One of our main objectives is to point out the implications of this identification problem for the analysis of earnings data. Though we cannot completely eliminate this difficulty, longitudinal data, which follows the same individuals over a period of time, allows us to identify more aspects of time than one could obtain from a single cross section. We provide a descriptive analysis of the exogenous changes in market conditions occurring during the period. No attempt is made to relate them to causal changes, such as past and expected future enrollment and government research grants. We find two basic tendencies: (1) Over the decade as a whole, scientists in academic institutions enjoyed better market conditions and thus a higher growth rate than those employed in private industry. (2) Toward the end of the decade, there is a marked reduction in the market's contribution to the growth rate. In some fields, such as physics, we note an actual reduction in the real earnings of new entrants. We conclude with a brief discussion of the changes in relative earnings over the decade by field and type of employer.

Analysis of Longitudinal Earnings Data: American Scientists 1960-70

The major findings of this study are as follows: (1) Simple cross section estimates grossly underestimate cohort profiles during the period 1960-70. Furthermore the growth in earnings is not uniform across experience groups and more recent vintages tend to have steeper profiles in most fields. Consequently the rate of return or present value comparisons based on cross sections are likely to be misleading even if the standard adjustment for growth is made. (2) For purposes of estimating mean profiles and mean effects of variables estimates based on pooled independent cross sections are quite close to those based on the more expensive longitudinal data. (3) There are important persistent unmeasured individual effects on both the level and growth of earnings. Consequently, individuals with the same observed characteristics will still have a wide variance in their permanent income.

The Dynamics of Marriage and Divorce

We formulate and estimate a dynamic model of marriage, divorce, and remarriage using 27 years of panel data for the entire Danish cohort born in 1960. The marital surplus is identified from the probability of divorce, and the surplus shares of husbands and wives from their willingness to enter marriage. Education and marriage order are complements in generating gains from marriage. Educated men and women receive a larger share of the marital gains but this effect is mitigated when their proportion rises. Education stabilizes marriage and second marriages are less stable. As the cohort ages, uneducated men are the most likely to be single.marriage, divorce, sorting

Return Migration, Human Capital Accumulation and the Brain Drain

In this paper we present a model that explains migrations as decisions that respond to where human capital can be acquired more efficiently, and where the return to human capital is highest. The basic framework is a dynamic Roy model in which a worker possesses two distinct skills that can be augmented by learning by doing. There are different implicit prices, in different countries and different rates of skill accumulation. Our analysis contributes to the literature on the selection of immigrants and return migrants by offering a richer framework that may help to accommodate selection of emigrants and return migrants that are not immediately compatible with the one-dimensional skill model. Our analysis also has implications for the debate on brain drain and brain gain. In the two skills model presented here, return migration can lead to a mitigation of the brain drain, or even the creation of a "brain gain", where those who return bring the home country augmented local skills.Return migration, human capital accumulation, comparative advantage, brain drain

The Earnings of Scientists, 1960-1970: Experience, Age and Vintage Effects

The purpose of this study is to present a simple but explicit model of on-the-job training which may enable us to separate and identify various types of vintage effects. An attempt is made to apply the model to the data on the earnings of American scientists in the period 1960-1970.