Debt and the Effects of Fiscal Policy

Empirical investigations of the effects of fiscal policy shocks share
a common weakness: taxes, government spending and interest rates
are assumed to respond to various macroeconomic variables but not
to the level of the public debt; moreover the impact of fiscal shocks
on the dynamics of the debt-to-GDP ratio are not tracked. We ana-
lyze the effects of fiscal shocks allowing for a direct response of taxes,
government spending and the cost of debt service to the level of the
public debt. We show that omitting such a feedback can result in
incorrect estimates of the dynamic effects of fiscal shocks. In par-
ticular the absence of an effect of fiscal shocks on long-term interest
rates-a frequent finding in research based on VAR's that omit a debt
feedback-can be explained by their mis-specification, especially over
samples in which the debt dynamics appears to be unstable. Using
data for the U.S. economy and the identification assumption proposed
by Blanchard and Perotti (2002) we reconsider the effects of fiscal
policy shocks correcting for these shortcomings.