Showing papers by "Institute for the Study of Labor published in 1976"

Health, Family Structure, and Labor Supply

Abstract: I consider the health, family structure, and labor supply inter-relationships at both a theoretical and empirical level. The paper is organized in the following way. SectionI introduces the material. In Section II, a theoretical model of family time allocation among market, home, and health activities is developed. The concept of a family health maintenance function is formalized to generate qualitative predictions of the effect of wages, health status, health care efficiency, and property income on the labor supply of husband and wife. In Section III, data from the older male portion of the National Longitudinal Surveys are used to estimate labor supply functions for married and single men with special attention to differences in poor health responses. A simultaneous model of male labor supply and other family income (chiefly transfer income and the earnings of the wife) is then estimated to determine whether variations in the work hours of males, largely due to health differences, induce any substantial changes in income producing activities by other family members. Finally, in Section IV the detailed time budget data on both males and females from the Productive Americans Survey are used to estimate more precisely the effect of health on total family time allocations. These data provide estimates of the impact of poor health on home production time as well as market time for both husband and wife.

Analysis of Longitudinal Earnings Data: American Scientists 1960-70

Abstract: 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.

A Multiplicative Model of Investment in Human Capital

Abstract: 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.

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

Abstract: 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.