The McKinsey Global Institute breaks the economy down into 60 sectors. U.S. workers are the most productive on earth in at least 50 of them. Productivity gains cause standard of living increases. Productivity gains lead to employment gains. If history is any judge, yesterday's excellent job numbers could mark the beginning of another surge in job creation.

As William W. Lewis, a former McKinsey partner, writes in "The Power of Productivity," about half the U.S. productivity gains have occurred in just two sectors, wholesale and retail trade. We've gotten really efficient at getting stuff from the hands of manufacturers to the hands of consumers. These innovations have had more important effects on how people really live than anything done in Washington.

Some of the effects have been entirely positive. In part because of scanners, companies now know how much stuff they are selling. Inventory-to-sales ratios shrink; companies are less likely to overproduce. That helps reduce the boom-bust cycle, which disrupts lives. During the first half of the 20th century, the U.S. economy was six times more volatile than it is today, according to a study by Bill Martin of UBS Global Asset Management and Robert Rowthorn of the University of Cambridge.

Other effects are double-edged. WalMart, a productivity powerhouse, gives middle class folks access to great products at great prices. It also decimates small merchants and contributes to the uglification of American suburbia.