Investment, the Capital Stock, and Economic Policy

Of the constituents of NTV only corporation tax and the hurdle rate seem credible targets for policy changes designed to boost labour productivity. The hurdle rate is stable over the long term so corporate investment usually responds to changes in RoE. It did so until 2000 but not since. The relationship between investment and corporation tax shows similar stability until the breakdown in 2000. These relationships provide the link between the level of investment and the growth of the capital stock. The sharp change in the investment response to favourable changes in tax and RoEs must have occurred because of an adverse change in one or more of the other constituents of NTV. But all constituents have changed in a favourable direction except the hurdle rate, whose change must have caused the current low level of tangible investment.