| Abstract: | In this paper, we explore the social rate of discount for public investment in a monetary overlapping generations model which allows for market disequilibria arising from price and wage rigidities. Financing public investment with a lump-sum tax on the younger generation, borrowing and money supply, the government maximizes the sum of generational utilities discounted by a social rate of time preference. For the social welfare optimum, it is required to take the boundary-maintaining policy by making demand for output equal to supply. In a stationary state, we show that (i) the social rate of discount on the Keynesian-repressed inflation boundary should be the weighted average of the social rate of time preference and the market rate of interest, the weights depending on the amount of private investment crowded out by public investment, and (ii) on the Keynesian-classical boundary it should be a modified version of the weighted average rule, containing an extra term which represents the marginal opportunity cost of public investment through its impact on labour employment. |
