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We
learned Friday that the
US
economy shed 4,000 jobs in August, the first decline in
payrolls since 2003. The bad news spread retroactively
to previous months, as the numbers for June and July
were revised down.
The
disappointing jobs report came on the heels of a series
of worrying signs that a credit crunch may be pushing
the US economy into recession. On the other hand,
indicators such as retail sales have been rosier. Has
the economy entered recession? And how could we tell if
it did?
A quick
look at the jobs numbers suggests that the negative
report is quite ominous. In the 692 months since January
1950, the employment change has been positive in 542
months and negative in only 150 months.
Employment changes have tended to be positive, of
course, because the economy has generally been
expanding. Since job changes are so coincident with the
rest of the cycle, negative months are concentrated in
recessions. Indeed, fully 77 percent of the jobs reports
during recessions showed negative job growth. Outside of
recessions, jobs were destroyed on net only 12 percent
of the time.
So,
seeing a negative month outside of a recession is pretty
unlikely. But it does happen. When is bad news bad
enough that alarm bells should go off?
The best
way to think about the problem is to use a recession
model that was pioneered by the brilliant economist
James Hamilton of the University of California at San
Diego. In a path-breaking paper in the distinguished
journal Econometrica published in 1989, Hamilton created
a model of the recession that is still the gold standard
for economists.
Revolutionary impact
The
Hamilton model is intuitively quite simple, but in
practice it has had a revolutionary impact on the way
economists view recessions.
The
model works like this: Assume that God sits in a room
with two urns (colored red and black) before him. Each
urn is filled with little balls that have numbers
written on them. In the black urn, the average number on
the balls is about two-and-a-half, but the numbers vary
widely. In the red urn, the average number on the balls
is about negative one-half, though the numbers also
vary.
Each
quarter, God pulls a number out of one of the urns, and
that number becomes US gross domestic product (GDP)
growth for that three-month period. In addition, he
tends to take a ball from the urn he drew from in the
previous period.
In this
setting, the problem for the econometrician is
relatively simple. He must identify at any given time
whether God is drawing from the red or the black urn.
Say we observe a negative GDP number. It might be that
the number is from the red urn, and that we have entered
a recession. It may also be that the draw was from the
black urn, and was just negative because of noise.
Next
report crucial
How can
you tell if the number was drawn from the red “recession
urn”? Hamilton’s model tells us that the key is what
happens next. If God made a bad draw from the good urn,
then the next draw will be back around two- and-a-half.
If he made a bad draw from the other urn, then the next
draw will be negative as well. As the sequence of
negative numbers builds up, our feeling that God is
drawing from the bad urn grows.
So a
crucial thing to watch will be the next report. If it,
too, is negative, then we will have had two such
employment reports in a row. Since 1960, we have never
had two consecutive negative employment months, except
for during or shortly after a recession. One could
reasonably conclude that God has turned to the red urn.
There will be lots of public opinion about a recession
between now and then, yet we won’t know until we see the
number.
Signs of
hope
Will the
next reading be negative? There are a couple of reasons
for hope.
First, a
key element driving employment south this summer was a
sharp decline in government employment. Employment
actually increased in private industry. It may be that
the reduction in government payrolls is a statistical
anomaly that will reverse itself shortly.
The
second piece of good news was highlighted last week by
Michael Darda, chief economist at MKM Partners, a
Greenwich,
Connecticut,
trading and research firm. Darda noted that unemployment
claims haven’t shown deterioration to this point,
something they should have done if the employment
situation were as bad as the latest report suggests.
That
gives Darda, and the rest of us, hope that the bad news
won’t get worse. |