Our GDP grew at 3.5% last quarter compared to the prior year’s 3^rd quarter, against economists’ expectations of a 3.0% growth rate. That’s good, right?

Why did it grow?

Part of the growth came from trade: imports fell sharply. Net trade is a definitional component of our GDP, and net trade consists of Exports less Imports. A reduction in imports, then, by definition elevates GDP.

This particular reduction, though, reflects a reduction in buying goods and services from overseas, which is entirely consistent with another trend: Americans aren’t buying stuff at any high rate, still.

In the 22 quarters since early 2008, real personal-consumption expenditure, which accounts for about 70% of US GDP, has grown at an average annual rate of just 1.1%, easily the weakest period of consumer demand in the post-World War II era.

[Note that the larger subject of the cite’s linked-to Elizabeth MacDonald article concerns our economy’s bailout impeded recovery.]

A larger part of the fall-off in imports, though, is the drop in oil imports. This also reflects a couple of factors: oil imports (imports generally) are measured in dollar prices, and the price of oil is down quite a bit from increased supply. The reason oil imports are down is due partly because we’re bringing smaller volumes of the stuff, but also because we’re spending less on what we do bring in. These two factors—reduced buying generally and the reduced price of oil—greatly reduce the impact of reduced imports generally on our economy. Imports are down because personal consumption is down and because it costs less to buy what we do import. These aren’t reflective of a sound economy.

The other side of that increased supply, though, is increased domestic production of oil (and of natural gas). Lower prices that result from that, both globally and domestically, are good for our economy, but the impact on the global price of oil—those import costs—really has little to do with hard goods being imported, or not.

There’s another factor in that apparently sound quarterly GDP growth rate: government spending in the form of defense spending. Government spending is another definitional component of our GDP, so whenever government spending increases, so does our GDP, regardless of any impact on our actual economy—the private sector, where Americans live and operate. I won’t go into how government spending crowds out private spending; that’s well covered in earlier articles of mine and in articles written by far sharper individuals than me.

It’s the particular government spending, defense spending, that’s of interest in this latest GDP growth number. Defense spending grew at its fastest rate in five years. There are sound reasons for that growth, but defense spending is highly volatile, as heavily influenced as it is by, not just big ticket items, but by huge ticket items, also. These huge ticket items include Navy and Air Force spending for (enormously expensive) ships and aircraft. Next quarter’s spending, next year’s spending, could easily be wildly different from the just concluded quarter’s.

Other factors in last quarter’s GDP growth rate are less encouraging—and they reflect conditions in our actual economy.

Growth in business investment—R&D, capital improvement, plant construction, and so on—slowed and fell well short of expectations. Business investment is a reflection of business owners’ expectation of future economic conditions; they’re unwilling to spend money today if the demand for their goods won’t be there tomorrow. Lack of such investment also means an anticipation of business income being unavailable for pay raises for existing jobs or for hiring for new jobs.

Also, consumer spending decelerated to a 1.8% rate. That’s us not spending (and not buying foreign goods).

That GDP number turns out not to be all it’s been cracked up to be.