There are at least two main ways to measure "the informal sector" of an economy, both of which entail difficulties. The effort is needed, however, because the underground economy accounts for about 13 percent of GDP in developed countries and almost three times that in developing countries.

In many ways, the European debt crisis is reminiscent of Latin America's experience in the 1980s, characterized by a period of high growth interrupted by an external shock. But there are some notable differences.