"But further analysis and experience soon raised doubts about the efficacy of these new tools. Empirical research indicated that the Keynesian multiplier was much smaller than earlier analyses had assumed, reduced by a crowding out of interest-sensitive spending caused by an induced increase in the demand for money and by the effect of the larger national debt on long-term interest rates. The leakage of demand through imports and the effect of the fiscal expansion on the exchange rate further reduced the multiplier."