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.

Dynamic Aspects of Earnings Mobility

This paper proposes an econometric methodology to deal with life cycle earnings and mobility among discrete earnings classes. First, we use panel data on male log earnings to estimate an earnings function with permanent and serially correlated transitory components due to both measured and unmeasured variables. Assuming that the error components are normally distributed, we develop statements for the probability that an individual's earnings will fall into a particular but arbitrary time sequence of poverty states. Using these statements, we illustrate the implications of our earnings model for poverty dynamics and compare our approach to Markov chain models of income mobility.

Human Capital Life Cycle of Earnings Models: A Specific Solution and Estimation

The purpose of this paper is to consider human capital models of earning behavior over an individual lifetime. A general class of life cycle models relating to individual earnings behavior is developed by considering alternative formulation of the basic Ben- Porath type model. An explicit solution to a specific formulation within this general class is considered in some detail. An empirical development of this explicit earnings function is estimated using data on a cohort of individuals surveyed at some point in their lifetime. The empirical estimates are discussed in detail. The estimated earnings function is then used to predict and individual’s discounted present value of lifetime earnings.

The Distribution of Earnings and Human Wealth in Cycle Context

The purpose of this paper is to outline a set of conditions under which human wealth is an index of well-being in a life cycle as prefatory to empirical estimates earnings and human wealth distributions for the1960 Census population.

Estimation of Permanent and Transitory Response Functions in Panels Data: A Dynamic Labor Supply Model

The purpose of this paper is to develop and test a dynamic labor supply model which incorporates the essential features of these previous models. The issues of permanent and transitory effects and of cross section versus time series can be addressed much more directly given the recent availability of panel data featuring repeated observation over extended periods of time of the same individuals. The labor supply model presented emphasizes the effect of permanent individual wage differences on permanent annual hours of work and the effect of serially correlated transitory individual wage variation on short run hours of work. Permanent and transitory deviations from the aggregate labor supply functions are also allowed. A by-product is an analysis of the relative roles of permanent and transitory components of both wages and hours in the distribution of earnings. The first section introduces the topic and describes related works. The second section provides a description of the essential features of the model. Section III provides a detailed outline of the empirical model and method of obtaining maximum likelihood estimates of parameters. Section IV provides a discussion of the results including the components of variation in wages, hours, and earnings. Comparisons are made by schooling group, by experience group, by union status, and by wife's work status. Finally the results are summarized in Section V.

Cohabitation, Marriage, and Divorce in a Model of Match Quality

The objective of this research is to develop and estimate an economic model of nonmarital cohabitation, marriage, and divorce that is consistent with current data on the formation and dissolution of relationships. Jovanovic's (1979) theoretical matching model is extended to help explain household formation and dissolution behavior. Implications of the model reveal what factors influence the decision to start a relationship, what form this relationship will take, and the relative stability of the various types of unions. The structural parameters of the model are estimated using longitudinal data from a sample of female high school seniors from the U.S. New numerical methods are developed to reduce computational costs associated with estimation. The empirical results are mostly consistent with previous literature but have interesting interpretations given the structural model.