This paper examines how ambiguous notions such as "meritocracy" , "equality of opportunity" and "equality of outcomes" can be given a formal content and related to more standard economic concepts such as social mobility, income inequality, and efficiency.

I consider an economy where skilled and unskilled workers use different technologies. The rate of improvement of each technology is determined by a profit-maximizing R&D sector. When there is a high proportion of skilled workers in the labor for ce, the market for skill complementary...

This paper offers and tests a theory of training whereby workers do not pay for general training they receive.

Social commentators from William Julius Wilson to Charles Murray have argued that increased sorting people into internally homogeneous neighborhoods, schools, and marriages is spurring long- run inequality. Calibration of a formal model suggests that these fears are misplaced.