Practitioners of development accounting assume that the private return on schooling equals its social marginal product. I show that this assumption is inconsistent with the mathematical structure of a multiplicative production function, which specifies that the private return is only a fraction...

We model an environment in which different vintages of capital with their different productivities coexist. A reduction in the cost of investment induces investment in new capital which raises both measured capital and measured productivity simultaneously. We calibrate this model to...