The value of human capital

How much is human capital worth? This is an important question when one this about the amount of resources that goes into education, both from public and private funds, as well as the substantial opportunity cost of attending school instead of working. The traditional approach is to compare the labor income of people with different levels of education and then come up with a return on investment or more often a return of one additional year of schooling.

Mark Huggett and Greg Kaplan take a different approach. They consider human capital to be an asset and decompose it into a bond (with fixed return), a stock (with variable return) and a residual. This becomes then a standard asset pricing problem. Then taking the labor income flow as a representation of the dividends from this portfolio, they can infer its composition, and how it changes over time. Using data for US males, it turns out the value of human capital is much lower than previously estimated. This is because the stochastic discount factor covaries negatively with earnings (they take into account capital income as well). Also, the bond component dominates the portfolio, especially for the college educated, which is not surprising given the large variance of income and employment among the less educated. What is more surprising, I think, is that stock market and human capital returns are not correlated. I would have thought that the business cycle would have had a strong impact there.