Investment, Capacity, and Output: a Putty-clay Approach

In this paper, we embed the microeconomic decisions associated with investment under uncertainty, capacity utilization, and machine replacement in a general equilibrium model based on putty-clay technology. We show that the combination of log-normally distributed idiosyncratic productivity uncertainty and Leontief utilization choice yields an aggregate production function that is easily characterized in terms of hazard rates for the standard normal distribution. At low levels of idiosyncratic uncertainty, the short-run elasticity of supply is substantially lower than the elasticity of supply obtained from a fullyexible Cobb-Douglas alternative. In the presence of irreversible factor proportions, an increase in idiosyncratic uncertainty typically reduces investment at the micro level but increases aggregate investment. Finally, we study the relationship between growth and uncertainty on aggregate capacity utilization and rates of machine replacement and investigate the factors that a ect the magnitude of replacement echoes.