MODELING INVESTMENT-SECTOR EFFICIENCY SHOCKS: WHEN DOES DISAGGREGATION MATTER?
比较了双部门模型（含部门特定生产率冲击）与单部门模型（含投资效率冲击）在分析投资部门生产率发展时的差异，发现两者对消费等变量的影响截然不同，尤其当放松与美国投入产出表不一致的条件时。
The most straightforward way to analyze investment‐sector productivity developments is to construct a two‐sector model with a sector‐specific productivity shock. An often used modeling shortcut accounts for such developments using a one‐sector model with shocks to the efficiency of investment in a capital accumulation equation. This shortcut is theoretically justified when some stringent conditions are satisfied. Using a two‐sector model, we consider the implications of relaxing several of the conditions that are at odds with the U.S. Input–Output Tables, including equal factor shares across sectors. The effects of productivity shocks to an investment‐producing sector of our two‐sector model differ from those of efficiency shocks to investment in a one‐sector model. Notably, expansionary productivity shocks boost consumption in every period, whereas expansionary efficiency shocks cause consumption to fall substantially for many periods.