Do unexpectedly larger government deficits coincide with unexpectedly higher inflation across countries?
Core argument: Across the IMF World Economic Outlook country sample, unexpected increases in public debt from unexpected deficits and from inflation over 2019–25 show a statistically significant positive relation.
To inspect the fiscal mechanism, I compare the IMF’s 2019 forecasts for the increase in the public debt over the next 5 years, with the actual increase that we saw. The IMF also puts out forecasts for each term in the accounting identity linking current to future debt in equation (7). Using these forecasts, I constructed the expected increase in debt due to expected inflation, interest rates, economic growth, and fiscal deficits. Then, using the April 2025 actual values for what each of these variables were, I constructed the actual increase in public debt due to the actual evolution of each of these four variables. Subtracting one from the other gives the unexpected increase in public debt, broken down into four unexpected terms, for each country in the WEO sample. Figure 9 plots two of these terms: the unexpected increase in public debt due to unexpected deficits, and the unexpected increase in the debt due to inflation in 2019-25 per country. The figure shows a clear positive relation, which is statistically significant. This says that for countries where deficits turned out to be higher than the IMF expected, inflation also turned out to be unexpectedly higher, using the common metric of their impact on the public debt. The fiscal mechanism is validated using the expectations data. If fiscal developments lead the IMF to raise its expected deficits, then this past experience should lead it to raise its expected inflation as well.

