by Calculated Risk on 10/14/2011 01:25:00 PM

Kelly Evans at the WSJ makes an interesting observation: Economy in Full Swing (Watch Your Head)

So far, incoming September economic reports have been surprisingly firm. Auto sales rebounded to their highest level since April. Chain-store sales posted year-on-year growth of 5.5%. The economy added 103,000 jobs, and manufacturing sentiment improved a bit. [Retail sales increased 1.1% in September]

...
If this feels like a 180-degree turn from August, that's because it basically is. It would be one thing if this were a special case, or a broad turning point in the economy. But, in fact, this kind of volatility, these jerky swings in growth, have become the norm. Consider what has happened so far this year: Real gross domestic product shrank in January and February, according to tracking firm Macroeconomic Advisers. Then it surged by more than 1% in March. It contracted again in May and June—only to jump by more than 1% again in July.

This isn't typical. Since 1992, monthly GDP has fallen about a third of the time when the economy hasn't been in recession. This year, even assuming a small gain in August, monthly GDP has fallen about half the time.

Monthly GDP isn't released by the Bureau of Economic Analysis (BEA). Evans is using an estimate from Macroeconomic Advisers.

The BEA does release monthly Personal Consumption Expenditures (PCE) data, and the following graph shows the monthly change in real PCE back to 1995.

Click on graph for larger image.

Real PCE has declined in three months this year through August (September will be positive based on the retail report). We have seen multiple declines in a year before - outside of a recession - like in 1995 and 2005. Many of the monthly declines were during recessions, but many monthly declines were event driven (like hurricanes Katrina and Rita in 2005). The sharp decline in September 2009 was due to the end of "cash-for-clunkers" (another event).

Although growth is sluggish - due to the significant slack in the system (excess capacity, lack of demand) and also high levels of household debt, I think the volatility this year can be blamed on a series of events including extreme weather (significant snow storms, flooding, hurricane Irene), the oil price increase related to the "Arab Spring", the tsunami in Japan, and the debt ceiling debate in D.C. during late July and early August.

Also the ongoing European financial crisis keeps flaring up and impacting the U.S. economy.

Yes, the economy is very sluggish - 103,000 jobs was a weak report, just better than low expectations - but I think the economic volatility is related to events and hopefully not some new normal.