ARE THE TWIN DEFICITS REALLY RELATED?

The emergence of record current-account and fiscal deficits in the United States during the 1980s draws increasing attention to what has become known as the "twin deficit" problem. Conventional wisdom is that a shift to larger government deficits entails a decline in government saving and results in larger trade deficits, Persistently large trade deficits are troublesome because they imply a transfer of wealth to foreigners and possibly a reduction in future generations' living standards.
This paper examines whether post-World War II data for the United States reveal a long-run secular relationship between the trade deficit and the fiscal deficit. The focus is on the secular relationship since that is the one most relevant to long-run policy concerns. The authors employ three different statistical techniques: (i) a deterministic technique for separating the secular components from the cyclical components to derive secular measures of the twin deficits, (ii) a stochastic procedure to isolate the secular components, (Hi) cointegration analysis to test for a long-run equilibrium relationship.
The authors conclude that, based on the first two approaches, evidence of a positive secular relationship between the twin deficits exists only under flexible exchange rates. This relationship appears quite strong–that is, a $1 change in the fiscal deficit eventually leads to roughly a $1 change in the trade deficit. On the other hand, findings based on cointegration analysis indicate no long-run equilibrium relationship between the twin deficits. This latter finding, however, may reflect a low power of the relevant statistical tests stemming from the shortness of the sample period.