Despite the hiring slowdown in the information-technology field, thousands of IT professionals and wannabes are banking on certifications to boost their careers.

Computer professionals use certifications as yardsticks of their skills in hopes of better jobs and higher pay. Employees in other fields may be lured by the thought that computer certifications might help them change to more lucrative or rewarding careers in IT.

Some take the exams to become certified at testing facilities, while others go online to be tested by new organizations getting into this lucrative field, estimated to be generating nearly $4 billion in revenues by 2003, reports IDC, a Framington, Mass., information-technology research firm.

But before signing up for a certification course on the Internet or at a local training facility, understand what computer technical training and certification in a particular technology, software program or operating system can and can't do for your career.

First, it won't guarantee you a job, say employers, recruiters and test-company executives. For some career changers, a certification is almost worthless because, while they may have learned enough to pass an exam, they don't know how to do the actual work. Second, a certification may not mean more money in a weekly paycheck in the current market. Lately, the average annual salary of certified professionals is less, not more, than in prior years, according to survey data.

Computer professionals can earn various types of certifications. Some are offered by vendors, such as Cisco Systems Inc. or Microsoft Corp. Among this type, Microsoft Certified Professional (MCP) or Microsoft Certified Systems Engineer (MCSE) are two of the best known. Others are offered by industry associations, such as CompTIA's A+, a basic hardware and software certification offered by the Computer Technology Industry Association in Lombard, Ill. A third type are those produced and administered online. A leading company in this category is Brainbench in Chantilly, Va.

While the number of people studying for certifications isn't known, more professionals are passing the tests. For instance, as of July 2002, there were nearly 1.3 million certified Microsoft professionals, up from 500,000 in 1999, reports Microsoft Certified Professional magazine, published by 101 Communications LLC in Irvine, Calif.

The most popular credential is the MCP, which was held by 789,364 people as of July 2002 and requires passing only one exam. There were 462,878 MCSEs, a credential that requires passing seven tests.

Brainbench has tested 1.2 million people since it was founded in 1998. The company will administer about 1.5 million exams to about 400,000 people this year, down from two years ago when it offered testing free of charge. After the U.S., Brainbench exams are most popular in India, the U.K., Canada, Australia and Russia.

But is it worth it to get certified? In a tight job market, where many highly qualified candidates are competing for openings, employers can hold out for what they want: actual on-the-job experience. Some place little or no value on certification when hiring candidates.

Just ask Gregory Cox. After taking retirement from the U.S. Navy, where he had worked as a civilian chemist for 30 years, Mr. Cox wanted to enter a field that would be challenging and interesting. At age 54, the Burke, Va., resident also wanted a profession that wouldn't discriminate because of his age. A computer buff, he enrolled in Chubb Institute's five-month network-engineering program at its Reston, Va., facility, graduating in October 2000.

The course cost $13,800, but he felt the expense was worth it because of the school's reputation with employers for turning out qualified graduates. Along the way, Mr. Cox earned his MCP and his MCSE.

Unfortunately, his IT career was short-lived. He landed one three-month computer assignment, then a one- and a two-week stint in IT that ended in June 2001. "Essentially, that was it," he says. "I was sidelined by the market."

He's now back in his old profession, doing research on rocket propellants for a McLean, Va., company. "At the time I decided to change careers, it was the right thing to do," says Mr. Cox, now nearly 56. "Sometimes you come out ahead on these things and sometimes, you don't. The market dried up, and other people had more experience than I had."

And nowadays, experience is what employers want. Sven James, president of CompuSven Inc., a Naples, Fla., software-product and services firm that helps companies convert e-mail platforms, says he hires only candidates whose backgrounds indicate they can achieve the results he wants.

"It's who will be the most productive, write the most code, provide the best support," he says. "For this sort of thing, I don't think certifications are that important, and we have found that people who are certified really aren't as good as the people who know how to program from going through a software-development cycle."

To Dan Wills, vice president of operations for USA-NET Inc., a Colorado Springs, Colo., computer-outsourcing company, a certification is a plus on a resume if it's backed up by relevant experience. But for a career changer from, say, the restaurant industry, who passes a certification exam after taking a six-week course, "their value is about as much as a restaurant manager with six weeks of classroom knowledge," he says. "In six weeks, you just aren't going to pick it up."

Brainbench's president and CEO, Mike Russiello, agrees that becoming certified won't guarantee someone a job. The main reason for gaining the certificate is to quantify your skills and show employers how well you compare with other candidates, which may get you an interview, he says. "I don't think certification is the answer to job-market issues, but it may help you articulate what you bring to the table," he says.

It's possible that if two candidates are otherwise equally qualified, the one with a certification might have an edge, say recruiters. "But it's really the real-world experience that gives them the edge," adds Kinga A. Wilson, president of IT Leaders Inc., a Lincoln, Neb., recruiting firm.

Ever-escalating salaries for IT pros appear to be a thing of the past. The average salary for all MCPs in 2002 is $52,000, down from $53,400 in 2001, MCP magazine reports. MCSEs with Windows NT 4.0 certifications earned average salaries of $59,800 in 2002, down from $62,700 in 2001, while MCSEs certified in Windows 2000 earned an average of $53,700 in 2002, down from $67,100 annually, according to the magazine.

Meanwhile, Cisco Certified Internetwork Engineers (CCIEs) in 2002 earn an average of $99,000, up from an average of $91,000 in 2001, but still down from an average of $115,402 in 2000, according to TCPmag.com, also published by 101 Communications. Lower-level Cisco certified pros saw salaries drop, but not as sharply.

Fortunately, certified professionals usually see their salaries gradually increase with experience. For example, an MCSE with 10 to 14 years of experience earned an average annual salary of $69,200 a year in 2002. But while certified Microsoft professionals usually make more than those without the credential, the tight job market rewards people with experience.

"Clients are asking for people with 10 years of experience," says Steve Satterwhite, president of Entelligence LLC, a Houston-based recruiting firm, "and even the people with really great experience are having a hard time getting a job right now."

Things won't stay this tight for long, according to a report on the information-technology work force. Companies shed a half million IT workers in the past year, but they'll need to fill 1.1 million new openings by mid-2003, according to a study by the Information Technology Association of America in Arlington, Va. Of those, 600,000 positions will remain unfilled due to a lack of qualified employees, the study forecasts.

Programmers will be needed more than other types of employees. Still, when asked how employees can advance, employers cited on-the-job experience as more valuable than certifications.

The emergence of online testing companies and the ease of taking tests online has initiated a debate over which certifications are best. All the certification groups update their tests as new technologies are introduced. However, the vendor and industry certifications are considered more rigorous and reputable because their exams are proctored at bricks-and-mortar locations, with test-takers showing identification before taking them.

Taking tests online is more convenient, but critics say there's no way to know the real identity of a test-taker. And some tests aren't very difficult, says Mr. Satterwhite. Just to "prove the point" about how easy the online tests can be, he registered and took an online Java-certification exam from a vendor he wouldn't identify. "I randomly picked answers and got certified as having intermediate skill sets," he says.

Only 35% of Brainbench test-takers pass its exams, says Mr. Russiello. The company offers more than 375 tests and ranks test-takers against others in their local vicinity, state or nationwide. For someone without Java skills to pass that exam "would be very unusual," says a company spokeswoman. The company will re-test candidates with Brainbench certifications at no charge if an employer doubts they lack the ability to have passed the exams, she says.

If you planned on jumping into network engineering after taking a crash course to become certified, you may want to change your strategy. But don't assume that all the cards are stacked against you. If you play your hand well, you can make the transition to the information-technology sector. The following suggestions from employers, trainers and recruiters may be helpful:

Seek knowledge, not a piece of paper. Your goal should be to qualify for a job, not gain a paper credential that you can't back up with hands-on ability. Instead of studying with a certification-training company, consider enrolling for an associate's degree or taking courses at a local community college or technical school.

"Some organizations teach to the test, others to the technology," says Ron Meints, president of Computer Personnel Inc., a Seattle recruiting firm. Research the course before you sign up.

Be ready to start at the bottom. No matter what you were earning in your last job, realize that you may have to start fresh and take a pay cut to enter the computer field. Ms. Wilson says she counsels career changers who have been certified in a computer skill but lack experience that they'll have to start in entry-level positions. "They have to forget about the salary they made before," she says. "Their best bet to get a job is to network and spread that net as wide as they can."

Seek experience as soon as possible. Instead of starting with certification, try to land an entry-level technical or help-desk job and work on your certification at night, Mr. Wills suggests. Employers are more likely to favor an applicant who has started working in the industry over someone who has stayed in an unrelated career field and sought a certification, say recruiters.