The maths behind the madness

By The Economist online

Our interactive guide to reducing government debt

GOVERNMENT debt dynamics, once an esoteric subject of interest only to macroeconomists, are suddenly in vogue. With Greece flirting with default, Italy's bond yields rising fast, and America's government bonds losing their AAA status, public-debt burdens have become dinner-party talk. Our interactive chart above shows current IMF forecasts but also allows you to input some basic economic assumptions to see where general government debt as a percentage of GDP might head.