That number is defended in a Forbes op-ed by Brian S. Wesbury and Robert Stein. Hit this link for the case as it’s been laid out. Plausible, yes. Probable, I’d say no.
From the link:
To be more precise, we are forecasting that real gross domestic product (GDP) grows at a 3.5% rate in the second half of 2009 and 4.5% next year. But, in all truth, we are much more confident about the overall 4%-plus figure for the full 18-month period than about the exact growth rate for any particular quarter. For example, if auto production ramps back up quickly enough in the next couple months, some of the extra growth set for 2010 might come late this year instead.
David Kirkpatrick 