The region's jobless rate slipped half a percentage point in April to 5.1 percent as construction and other seasonal industries began spring hiring.

The number of employed residents, even after adjusting for such seasonal variations as construction, rose 3,700 from March to 1,156,800, the state Department of Labor and Industry said.

A separate measure of payroll jobs, considered by most economists to be more reliable than the household survey, showed that the number of nonfarm jobs in the region rose 3,400 from a year ago, the eighth straight month payroll jobs have been higher than the prior year's level. For the first four months of the year, nonfarm jobs are running about 4,000 above year-ago levels.

Despite the improvement on the jobs front, the region's labor force, defined as those working or actively looking for work, shrank slightly during the month in the seven-county area of Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland.

A contracting labor force indicates would-be workers are uncertain about the economy and quit looking for jobs. It could suggest workers are still not convinced that the situation is all that much better in a region that lost some 24,000 jobs from 2001 through 2003. Or it could simply be a statistical variation or a sign that the region's population isn't growing.

Whatever the reasons, April's jobless rate was down considerably from March's 5.6 percent and was lower than the nation's 5.2 percent rate. However, it remained above the state's 4.9 percent rate for April.

During the month, the local construction industry added 4,300 jobs, boosting employment in that sector to 52,000.

More than half of that increase came from specialty contractors.

The broad category of trade, transportation and utilities also gained 1,600 jobs, for a total of 231,500.

Retail trade, the largest segment, added 1,300 jobs, including about 500 at building material and supplies dealers. But the transportation and warehousing industry also added workers despite ongoing layoffs at US Airways.

Professional and business services grew by 2,100, aided by growth in landscaping and tax preparation, and the seasonal leisure and hospitality industry added 4,100 jobs during the month.

Manufacturers also added 200 workers during April, but at 101,300, employment in that sector remained 2,000 below last year's level.

Growth in the region's manufacturing sector slowed slightly in April, according to a monthly survey of purchasing agents conducted by the Pittsburgh chapter of the Institute for Supply Management.

But the slowdown was offset by stronger growth in the nonmanufacturing sector, it said, bolstered by higher prices and export orders.

Overall, the group said, its Regional Economic Index, a monthly gauge of local activity, rose slightly to 51.836 from 51.805 in March. A reading above 50 reflects expansion.