Threshold Effects of Capital Stock in the Public Capital Productivity In the economy of the Iran Using a smooth transition regression model

Improving capital efficiency is one of the most effective methods for increasing the rate of economic growth and one of the factors affecting capital productivity is the rate of capital utilization. In this study, using the annual data of Iran's economy during the period of 1979-1959, and using the nonlinear model of soft transfer regression (STR), we investigated the effect of government capital stock on capital productivity in Iran. Initial tests confirming the nonlinear relation between the stock of government capital and the production and acceptance of the state capital stock as the transfer variable, in the first regime, when the stock of government capital is less than the threshold, the effect of this variable on negative production, and in the second regime, the amount of storage The capital of the state is more than the threshold; the accumulation of state capital has a more negative and significant effect on production. These results mean that the accumulation of government capital in Iran during the reviewed period has had a negative effect on the effectiveness of the stock of government capital on production (as an indicator of the productivity of government capital).