This morning’s much anticipated fourth quarter GDP release provides a preliminary estimate of real GDP growth of 2.8 percent. To be fair, perhaps the anticipation is experienced mostly by forecasting economists and financial market watchers. I am always particularly interested in fourth quarter as it closes out the year and in this case I forecasted an increase in growth of 2.2 percent, up from third quarter’s 1.8 percent growth.

The estimate is higher than my forecast by a fair amount actually, but in the grand scheme of forecasting, forecast errors, and the direction of change, I am reasonably happy. I had forecasted the increase in growth with trepidation because the economic fundamentals remain weak.

The fourth quarter data implies that the economy grew 1.7 percent in 2011, compared with 3.0 percent in 2010.

What were the drivers of the increase in fourth quarter growth? Consumption and Investment expenditures both rose, $50b and $80b respectively, trade was little changed, and government expenditures fell about $30b.

Investment expenditures are driven by a four main components, business structures, equipment and software, residential, and inventory investment. All of these components are volatile, but one of them, inventory expenditures, is super volatile. Sure enough, about $55b of the $80b investment expenditure increase was due to inventory investment. I hope that the shelf-stocking was not overdone for if it was, there would be a slowdown in inventory investment this quarter.

Another interesting movement within Investment was residential, up at an annualized growth rate of about 11 percent. While residential investment in states like Nevada, California, Florida remain at historic lows, it is booming in states like North Dakota, Oklahoma, and Texas. We can thank the middle part of the country for this source of growth.

The $30b pullback in government expenditure breaks down to a $20b decline in Federal and a $10b decline in State/local expenditures. The Federal change was due to a defense spending contraction, as non-defense expenditures rose slightly.

Inflation, as measured by the GDP deflator, fell dramatically from 2.6 percent in third quarter to 0.4 percent in fourth quarter. Subdued inflation in a time of relatively high unemployment is a good thing, as it helps those unemployment or partially-unemployed households manage expenses.

The BEA measure of the personal savings rate fell from 3.9 percent in third quarter to 3.7 percent in fourth quarter. This worries me, as household debt levels are still high. I have argued this before and will do it again: consumption in an era of high household debt does not help the economy. What is needed is savings and investment. Future growth depends on it.