About those economic stats...

Every once in a while we get reminded that the government reports that everybody pays so much attention to are only estimates of what's going on - and subject to wide variance. The WSJ's Carl Bialik (aka "The Numbers Guy") provides a good primer. Did you know, for example, that the number of out-of-work Americans in March grew by 134,000 - or possibly 500,000? Or it might have actually fallen by 200,000.

In fact, at a time when high unemployment tops many people's worries about the economic recovery, the [Bureau of Labor Statistics] can say only that it is 90% confident that the true change in the number of unemployed in March was somewhere between a drop of 243,000 and an increase of 511,000. In other words, it isn't even clear whether the number of unemployed rose or fell last month. The ranges are similarly broad for seven of the last 10 months--and for more than 75% of the time in the past decade.

This isn't a failing of government or of statisticians, say economists. Instead, it is the inevitable result of trying to measure small changes in a sprawling, complex economy. There is no doubt that the unemployment rate remains near the highest it has been in decades. But the government doesn't really know how much that rate has been changing from month to month, which can be vexing for economists attempting to identify signs of a nascent recovery.

A good recent example is the California unemployment rate that went from 12.5 percent in February to 12.6 percent in March. Statistically, it was a nonevent that received way too much news coverage. Why? Because the old journalism rules require that all things are either moving on up or moving on down, even when they're not.