When Stephen Clark decided to get an MBA, he set his sights low.

"I know I'm not even close to any of those 'name' schools," he says of the for-profit University of Phoenix, where he is seeking a master's degree in business administration. "I think they probably have a lot more rigorous structure. I'm not up every night till 3 o'clock doing homework. I hate to say it's a lesser degree, but it's preparing you differently."

Even so, Clark, 51, said he believes the University of Phoenix is a good choice for him. A director of business development at the U.S. Army's Aberdeen Proving Ground, the Bel Air, Md., resident was looking for a way to get an MBA while holding down a job and even "maintaining something that passes for a social life," he said. His boss had encouraged him to get the degree to qualify for a promotion.

Clark is far from alone. Motives such as his have prompted more and more people to seek MBAs from for-profit institutions such as Phoenix in recent years. That's evident in these schools' revenue growth: More than 30 percent each of the past three years, according to research firm Eduventures Inc.

That growth is only possible because schools such as DeVry University, ITT Technical Institute and Corinthian Colleges are anything but selective, as opposed to the top traditional nonprofit universities.

They generally impose low or no requirements in the areas of test scores and undergraduate grade-point averages, and they grant thousands of degrees every year. As experts increasingly question the value of an MBA from any but the top 10 or 20 schools in the country, many doubt whether a for-profit degree is worth the cost.

"For clients who care about the MBA background, a Top 20 or even Top 50 MBA degree is the only cost-justified degree," said Marc D. Lewis, North American president of the executive search firm Morgan Howard Worldwide. He said an executive MBA program or even a few business courses can be of as much value as a for-profit degree.

"If you cannot get into a top-tier MBA program, you should look hard at whether you would be able to learn the MBA-type skills in a different setting," he said.

Representatives at institutions such as Phoenix counter that their students aren't in the same position as, say, a recent college graduate hoping to get his foot in the door at a major company. They're working adults who, like Clark, want a degree to bolster their skill set.

That's Michael Valasek's rationale. Valasek, a classmate of Clark's and another Bel Air resident, said that at 26, he's the youngest person in his program, which is filled with mid-career workers.

"I simply want the credential to fall back on," he said. "I know it's not going to get me a promotion. I just want [it] for the future, for a possible consulting role. An MBA is much more desirable to some organizations than someone with a bachelor's trying to do consulting."

Even within the world of for-profit institutions, there are tiers -- as Robert S. Silberman, chief executive of Arlington-based Strayer University, is quick to point out. Strayer is accredited by the Middle States Commission on Higher Education, which also accredits such well-regarded schools as American University and Carnegie Mellon University.

"We've been around for over 100 years," Silberman said. "We have a very long track record of employers hiring a significant number of Strayer MBAs."

Not surprisingly, Silberman downplays the value of a degree from a Top 10 institution. "The 'name' value of a degree is really very ephemeral. As the CEO of a company, what I'm most interested in is the training in analytic and cognitive skills [an MBA] gives a potential employee," he said.

Ultimately, you must consider exactly what such an MBA can do for your career. As for the classes themselves, Clark notes that the content can seem overly theoretical to someone who is already holding down a job. He said it's important to stay focused on how you will use your lessons.

"I try to take at least a couple of 'take-aways' from each class," he said.

"I'm gaining a lot of confidence in making decisions. I used to just use gut feelings, but now I can say I did a survey or a study to make a decision I can sell management."