RSS RSS

Quarterly Review 2242

A Defense of AK Growth Models

Ellen R. McGrattan Consultant

Fall 1998

Abstract
AK growth models predict that permanent changes in government policies affecting investment rates should lead to permanent changes in a country’s GDP growth. Charles Jones (1995) sees no evidence for this prediction in data for 15 OECD countries after World War II: rates of investment, especially for equipment, have risen while GDP growth rates have not. This article provides evidence supporting the AK models’ prediction. Data back to the 19th century show a strong positive relationship between investment rates and growth rates and short-lived deviations from trends. A strong positive relationship also exists between average rates of investment and growth in postwar data for a large cross-section of countries. To account for the short-run deviations in rates that Jones highlights, the model he used is extended to allow policies to affect not only investment/output ratios but also capital/output ratios and labor/leisure decisions.


Download Paper (PDF)

Additional Files (FTP)