Inequality of opportunity and growth

Theoretical and empirical studies exploring the effects of income inequality upon growth reach a disappointing inconclusive result. This paper postulates that one reason for this ambiguity is that income inequality is actually a composite measure of inequality of opportunity and inequality of effort. They may affect growth through opposite channels, thus the relationship between inequality and growth depends on which component is larger. Using the PSID database for the U.S. in 1970, 1980 and 1990 we find robust support for a negative relationship between inequality of opportunity and growth, and a positive relationship between inequality of effort and growth.