Real gross domestic product -- the output of goods and services produced by labor and property located in the United States -- increased at an annual rate of 2.5 percent in the first quarter of 2013 (that is, from the fourth quarter to the first quarter), according to the "advance" estimate released by the Bureau of Economic Analysis. In the fourth quarter, real GDP increased 0.4 percent. The Bureau emphasized that the first-quarter advance estimate released today is based on source data that are incomplete or subject to further revision by the source agency (see the box on page 3 and "Comparisons of Revisions to ... (full story)