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Traders work on the floor of the New York Stock Exchange on January 28, 2013 in New York City. Coming off four straight weeks of gains, U.S. stocks opened lower Monday with The Dow Jones industrial average down 0.2%.

Economic growth shrank in the last quarter of 2012, according to a preliminary report by the Commerce Department. The nation's output of goods and services decreased slightly, after growing at an annual rate of more than three percent in the previous quarter.

Is this an aberration or a sign of bad things to come?

Joining us for some analysis is Ryan Avent, economics correspondent for The Economist.