In the economic forecasting business, there's nothing tougher than recognizing new trends.  When the fundamental relationships that govern how the economy evolves themselves change, the wheels fall off most forecasting models.  We forecasters spend our professional lives in search of stable, predictable linkages between pieces of the economic puzzle, and we don't deal with events that upset them very easily.

But those events do come along from time to time.  Prior to the 1980's, growth in the U.S. economy was highly variable, producing a recession, on average, about every five years. Interest rates, unemployment rates, and inflation rates all frequently spiked up to double digit levels, and phrases like "stagflation" and "the misery index" found their way into our conversations.

Then something happened.  The Federal Reserve got inflation under control, and the economy started behaving like a choir boy.  Not only did the intervals between recessions almost double, but the growth that unfolded between those downturns exhibited little of the volatility that was so common in the past.

Very few of us saw that coming. Worse yet, many of us in the years since have seen things coming that were never there. Remember the fear that Japan, Inc. would dominate the world economy? Or the predictions of a 35,000 Dow?

We must keep these thoughts in mind as we examine two very new -- and very passionately argued -- claims of new trends in the American economy.  These are the growth in the Chinese economy, and the lack of growth in U.S. employment.

To some people's thinking, the two are directly linked.  It is easy to conclude that the economic emergence of China has come at the cost of job growth here in the U.S. , especially in the manufacturing-intensive Midwest .  Its low-cost labor pool has been a magnet for labor-intensive industries to relocate, and its flood of exports has produced a large and growing bilateral trade surplus with the U.S.

But those who project that new trend forward to warn of a future where domestic manufacturing ceases to exist are going over the edge.  A more careful look at the data reveals that most of the export jobs being created in China already left the U.S.economy years ago.  In this sense,China is more of a threat to countries like Taiwan and Singapore , who have seen their cost advantages undercut by their populous neighbor, than it is to us.

Besides, even if manufacturing employment has accelerated downward in recent years, manufacturing output has not.  The fact that the economy's overall productivity has skyrocketed in the last year should tell you something about the kinds of jobs being lost.

Which brings us to a second new economic trend spotted by some -- the inability of the U.S. economy to create net new jobs.  It's a disappointing outcome that stands in contrast to the strength evidenced in almost every other indicator.  It has also made palatable the otherwise-absurd notion -- set forth by some presidential candidates -- that we need a "plan" to overhaul an economy that has grown at rate faster than its historical average for two consecutive years.

Look for the data to put this notion to rest in the upcoming months.  The productivity gains that have helped pull off this jobless growth cannot be sustained, and the pressure of low inventories in the face of faster growth will force companies to add to payrolls in a much bigger way.  If that's the case, it will be one more false trend to put behind us.