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...

From 1870 to 2000, the workweek length of employed persons decreased by 41 per cent in industrialized countries. The employment rate, employment per working age person, displays large movements but no clear secular pattern. This motivated the question: What accounts for the large decrease in the...