| This dissertation consists of three self-contained essays that address issues crucial for the understanding of economic growth.; The focus of the first essay is on the measurement of human capital.; In the essay, I construct alternative measures of human capital for the United States using data from the Bureau of Labor Statistics. I construct various education-based measures of human capital, including the average years of schooling. The main contribution of the essay, however, is a measure that broadens the concept of human capital to include work experience as well. The experience dimension of this measure is appealing since it essentially captures skills accumulated outside the formal educational system, such as on the job training or learning by doing.; The second essay is an empirical investigation of R&D-based endogenous growth models. Central to these models is a knowledge production function that describes the evolution of knowledge creation. According to that function, the yate of production of new knowledge depends positively on the amount of labor engaged in R&D and the existing stock of knowledge available to these researchers. The dependence of new knowledge on the existing stock is intended to capture intertemporal knowledge spillovers.; The main result of the study is that knowledge spillovers are large. The estimated long run elasticity of new knowledge with respect to the existing stock of knowledge is at least as large as unity. The study interprets this evidence in light of existing R&D-based growth models. Furthermore, it provides a new interpretation of the observed weak relationship between the number of research workers and TFP growth.; In the third essay, I estimate an aggregate production function for the U.S. economy over the postwar period. In addition to private capital and raw labor, I expand the production function to include the stock of public capital, human capital, and the stock of knowledge as additional factor inputs. The main results of the essay suggest that there is a strong long run positive effect of public capital, human capital, and the stock of knowledge on aggregate output. The essay also demonstrates that the production function should be looked at as a cointegrating system, and hence the results in the essay may invalidate results based on the estimation of production functions in first differences, and those using single-equation-based cointegration tests. (Abstract shortened by UMI.)... |
