Author(s): Katia Berti
Stochastic projections are a powerful tool to feature uncertainty in macroeconomic conditions into the analysis of public debt dynamics. They allow simulating a very large number of debt paths, corresponding to as many shock constellations to the non-fiscal determinants of debt evolution (short- and long-term interest rates, growth rate and exchange rate). Furthermore, random shocks are simulated in a way to reflect the size and the correlation of historical shocks. The specific approach for stochastic projections used here, based on the variance-covariance matrix of historical shocks, further allows defining a "central scenario" (for which we use ECFIN's Autumn 2012 forecasts), around which shocks apply. The paper applies this methodology to 24 EU countries over 2013-17. Cross-country differences in the variance of the debt-to-GDP ratio distributions (reflecting differences in historical volatility of macroeconomic conditions) emerge clearly from the simulations. This shows the importance of allowing for a more comprehensive and country-tailored assessment of downward and upward risks to debt dynamics. This stochastic framework also has the distinctive advantage of allowing for an explicit probabilistic assessment of debt projection results. A closer scrutiny of three EU countries in the case with temporary shocks reveals, for instance, that the most likely outcome for IT over 2013-17 is a decreasing path for the debt ratio (though this is projected to be still higher than 116% with a 50% probability in 2017). For ES, simulations show an increasing path over the projection horizon for all shock constellations, with an 80% probability of a debt ratio greater than 100% in 2017. Finally, for HU, we obtain a 60% probability that the debt ratio stabilises or reaches higher values from 2013 onwards, with a 40% probability of a debt ratio greater than 80% in 2017.
|ISBN 978-92-79-28562-2 (online)|
|doi: 10.2765/4211 (online)|
Economic Papers are written by the staff of the Directorate-General for Economic and Financial Affairs, or by experts working in association with them. The Papers are intended to increase awareness of the technical work being done by staff and to seek comments and suggestions for further analysis. The views expressed are the author’s alone and do not necessarily correspond to those of the European Commission.