Related Web Links - Module 10 - The Circular Flow and Gross Domestic Product
Measuring the size of the economy using GDP or GNP is standard practice. Economists rely on these measures to review and predict trends in an economy.  However, it is argued that a substantial amount of economic activity is left out of the full measure of a country’s performance.  Among the activities excluded are underground activities (shadow economies) such as illicit drug trade, working off the books and services provided by homemakers (stay-at-home moms or dads).
The following links and articles provide some insight into this perspective:
Schneider, Friedrich with Dominik Enste “Hiding in the Shadows: The Growth of the Underground Economy”; http://www.imf.org/external/pubs/ft/issues/issues30/index.htm
“Study: Stay-at-Home Mom Worth Nearly $117,000 a Year,” http://www.chron.com/disp/story.mpl/nation/5765931.html
For the Bureau of Economic Analysis’ National Economic Accounts, components of GDP in broad categories (C, I, G, imports, exports), and detailed accounts go to:   http://www.bea.gov/national/Index.htm.