Many economists consider temporary employment to be a leading indicator of broader corporate hiring. Companies that are running into hard times and need to cut staff, for example, will cut temporary workers before laying off regular employees. Similarly, when business is perking up after a recession, firms may be more inclined to hire temporary staff out of uncertainty of whether the good times will last.

The Labor Department classifies such temporary workers in the "employment services" category of work, a category that has predicted the trajectory of the job market in recent years. In November 2000, for example, the region was adding jobs at a 4.1 percent pace compared with the same month a year earlier. But the number of employment services jobs had already started shrinking, down 0.9 percent for the year ended that month. The Washington area did not lose jobs until 11 months later, in October 2001.

Similarly, the number of local employment services jobs perked up at a 1.7 percent pace back in August, when job growth in all sectors was at 0.7 percent. The indicator is not perfect, though. For example, employment services cut jobs in the first half of 2003 even as the regional economy as a whole was growing marginally.

The most recent data suggest continued good times could be ahead. Local employers added 3,900 temporary jobs in the year ended in April, an 8.7 percent rise.

-- Neil Irwin