Last week I pointed out a somewhat mysterious, undated entry (turned out to be Nov. 24, 2009) at the website of the “official” arbiters of recession, the NBER.

Rooting around the web, and finding myself at the site of the Census Bureau, I caught the following cryptic note at the page where Durable Goods data is released:

The Census Bureau identified a processing error that occurred when revising historic seasonally adjusted data for the November (data month) releases. The data have been corrected. As of January 15, 2010, revised data from January 2001 through October 2009 are available in the Historical Timeseries – NAICS tables, under the Historical Data tab.

Being skeptical and curious, I wondered what this “error” implied for the most recent release of Durable Goods (because we’re always all about the latest green shoot, right?).

Here we go again.

It struck me as a bit unusual that the data had been corrected as of January 15 — not coinciding with a scheduled Durable Goods release, which actually comes this Thursday, the 28th. Seemed to be a slip-it-in-there-while-no-one’s-looking type of thing. (And no, I’m really not a conspiracy theorist.)

But back to the November data: You may recall that consensus for November’s Durable Goods had been +0.5%. The reported data was lighter than expected at +0.2%. Looking at the revisions the Census Bureau has now incorporated into the data, we see that November actually printed at -0.7%.

Here are the “Before” and “After” charts:

Before

After Revision

Admittedly October was bumped up a bit. But we now are looking at two consecutive months of declines, which we’ve not seen since December 2008 (-3.7%) and January 2009 (-7.9%), when the world was falling apart. And the trend seems to have deteriorated, with November now being the worst print since August. What might the real-time impact have been had the Census Bureau initially reported a disappointing -0.7% instead of the +0.2% they maintained until very recently?

Consensus for Thursday is around +1.5% – +2.0%. Stay tuned.