The Replacement Problem in Frictional Economies: A near-Equivalence Result
通过校准的劳动力市场摩擦模型，比较了“创造性破坏”与“升级”两种经济模式，发现它们对工资不平等和失业的影响非常相似，且摩擦产生的工资不平等很小，因为美国经济中失业和职位空缺持续时间很短。
We examine how technological change affects wage inequality and unemployment in a calibrated model of matching frictions in the labor market. We distinguish between two polar cases studied in the literature: a “creative destruction” economy, where new machines enter chiefly through new matches and an “upgrading” economy, where machines in existing matches are replaced by new machines. Our main results are: (i) these two economies produce very similar quantitative outcomes, and (ii) the total amount of wage inequality generated by frictions is very small. We explain these findings in light of the fact that, in the model calibrated to the US economy, both unemployment and vacancy durations are very short, i.e., the matching frictions are quantitatively minor. Hence, the equilibrium allocations of the model are remarkably close to those of a frictionless version of our economy where firms are indifferent between upgrading and creative destruction, and where every worker is paid the same market-clearing wage. These results are robust to the inclusion of machine-specific or match-specific heterogeneity into the benchmark model.