The Commerce Department this morning announced its advance estimate of last quarter’s real GDP. As expected, the estimate shows that GDP fell in the first quarter of 2009 — by a hefty 6.1 per cent at an annual rate. An implication is that the current recession has just tied the post-war record for longevity.

The previous record-holders were the recessions of 1973-75 and 1981-82, each of them four quarters in length according to the official NBER chronology.  In the current downturn, the NBER’s Business Cycle Data Committee determined that the economy peaked in the 4th quarter of 2007. Although the Committee won’t declare the trough of the recession until well after the fact, and the trough could well be a ways off, a negative 1st quarter of 2009 almost certainly means that the four-quarter benchmark has now been attained.  (The Commerce Department often revises its GDP figures substantially between the advance estimate and the final number, and we are due for major backward-looking revisions in July.  Indeed that is one reason why the NBER always waits so long to issue its findings.  In the past, the size of the average revision has been just over 1 percentage point, whether up or down.   It is highly unlikely that future revisions will change this morning’s negative number into a positive one.)

The NBER also keeps a more precise monthly chronology. The postwar record is 16 months, again shared by the 1973-75 and 1981-82 recessions. To match this monthly benchmark, the current downturn would have to have continued into April. Our best single indicator as to whether it did so will be the employment number to be released by the Bureau of Labor Statistics next Friday, May 8. It almost certainly will show that there were further job losses in April. If so, it will further confirm the dismal conclusion: one would have to go back 80 years, to the disaster of 1929-1933, to find a longer recession.