Is this the start of a recession? According to the US Dept. of Commerce Real gross domestic product (GDP) -- the output of goods and services produced by labor and property located in the United States -- decreased at an annual rate of 0.1 percent in the fourth quarter of 2012.  A recession is usually defined  as two consecutive downward GDP quarterly reportsKeep in mind that this estimate will be revised at the end of February and again at the end of March (which  means it could go down or up). The decrease in real GDP in the fourth quarter primarily reflected negative contributions from private inventory investment, federal government spending, and exports that were partly offset by positive contributions from personal consumption expenditures (PCE), nonresidential fixed investment, and residential fixed investment. Imports, which are a subtraction in the calculation of GDP, decreased. The downturn in real GDP in the fourth quarter primarily reflected downturns in private inventory investment, in federal government spending, in exports, and in state and local government spending that were partly offset by an upturn in nonresidential fixed investment, a larger decrease in imports, and an acceleration in PCE. Final sales of computers added 0.15 percentage point to the fourth-quarter change in real GDP after adding 0.11 percentage point to the third-quarter change. Motor vehicle output added 0.04 percentage point to the fourth-quarter change in real GDP after subtracting 0.25 percentage point from the third-quarter change.