September 2003

Modeling Aggregate Investment: A Fundamentalist Approach

John M. Roberts

Abstract:

This paper applies some lessons from recent estimation of investment models with firm-level data to the aggregate data with an eye to rehabilitating convex costs of adjusting the capital stock. In recent firm-level work, the response of investment to output and other "fundamental" variables is interpreted in terms of the traditional convex-adjustment-cost model, implying annual capital-stock adjustment speeds on the order of 15 to 35 percent. In aggregate data, I find that this "fundamentalist" model can account for the reduced-form effect of output on investment and the estimated capital-stock adjustment speed is similar to those from firm-level studies B--around 25 percent per year. To account for the slower adjustment to changes in the cost of capital, I consider a model in which the capital-intensity of production is also costly to adjust. I find that this model can account for the reduced-form effects of both output and the cost of capital on investment.

Keywords: Investment, adjustment costs, putty-clay

PDF: Full Paper

Disclaimer: The economic research that is linked from this page represents the views of the authors and does not indicate concurrence either by other members of the Board's staff or by the Board of Governors. The economic research and their conclusions are often preliminary and are circulated to stimulate discussion and critical comment. The Board values having a staff that conducts research on a wide range of economic topics and that explores a diverse array of perspectives on those topics. The resulting conversations in academia, the economic policy community, and the broader public are important to sharpening our collective thinking.

Back to Top
Last Update: January 11, 2021