Testing job skills can be a vexing experience. Sure, experts consider it the best predictor of job performance, but testing programs are pricey. Full-fledged programs in companies with 100 employees can cost from $15,000 to $50,000.

The U.S. Department of Labor can help companies that can't afford such programs. Here's what you do: call one of its 1,700 U.S. Employment Service -- or Job Service -- offices (usually in the blue pages of the telephone book, under "State Government") and place a job order and request for testing with the office. If the office determines a test is appropriate, and you want it to test and screen the job hunters you've found, you may agree to send to the employment office all those who respond to your ad. After evaluating candidates on the basis of test scores, experience, education, and other factors, the office will notify you of the best candidates. These are the three general areas of testing available:

* Clerical skills. This test covers the basics: typing, spelling, and dictation.

* Literacy skills. A test designed to measure reading and mathematical abilities.

* General Aptitude Test Battery (GATB). This test of nine aptitudes assesses verbal, mathematical, perceptual, and psychomotor abilities. It's also available for nonreaders and in Spanish. The Department of Labor may suspend use of the GATB, however, since it has been charged with being discriminatory against minority groups.

"Tests can be tremendously useful because they work," says John Hinrichs, president of Management Decision Systems, a consulting firm in Darien, Conn. The cost of a bad hire? "About three times the employee's salary," he says.

-- Ellyn E. Spragins