A few years ago, Jeremiah Bishop, a new college graduate from Campbellsville University in Kentucky, found a job as an entry-level accountant at an accounting firm. He also found a mentor.

The firm had recently set up a formal mentoring program to help new employees get acclimated to the public-accounting profession. Mr. Bishop was paired with a senior manager. But over the next eight months, he and his mentor met only sporadically for lackluster conversations. Eventually, the tenuous relationship petered out.

Looking back, he said the firm never bothered to follow up to see if the relationship was working out. "I had really high hopes and had all these ideas," said Mr. Bishop, now an accountant for a Louisville, Ky., restaurant company. "Now, as far as mentoring goes, I'd rather just do my own thing."

During the past few years, many employers have embraced formal mentoring programs as a way to connect lower-level employees with senior executives. But these formal mentoring relationships often don't work out the way the employers hope. Many of the programs aren't regulated. Employees may end up matched with people with whom they're incompatible. Mentors and those they help also say it is tough to stay enthusiastic about a "forced friendship." The biggest complaint from those being mentored is neglect.

"Formal mentoring is often compared to computer dating -- sometimes it works and sometimes it doesn't," said Belle Rose Ragins, a professor at the University of Wisconsin at Milwaukee who has conducted extensive research on mentoring.

"We have just found that informal mentoring is more effective," she said.

Formal mentoring programs may work better in some industries than in others. High-tech and manufacturing companies appear to have had better success with formal mentoring programs, while people at law firms seem to struggle, experts say.

"Once someone has made partner at a law firm, he or she has become an independent, so it's a lot harder to make formal mentoring work in this kind of environment," said David Wilkins, a professor at Harvard Law School. "It actually doesn't work at all."

Betty Owens, director of attorney development at the big Houston law firm Vinson & Elkins LLP, said her firm is launching a mentoring program for its new associates this fall and is addressing the battle "on several fronts."

First, each new associate will be matched with a midlevel associate and a partner. The firm developed a handbook that lists the guidelines for the program and responsibilities for both mentors and those being mentored. The handbook, which helps ensure that everyone in the mentoring relationship knows what to expect, attempts to avoid the problem of mismatched expectations that can arise when responsibilities aren't spelled out.

Every few months, Vinson & Elkins will have an event to give the participants the opportunity to share information about good mentoring practices. In January, the firm will launch a mentoring program for second-year and third-year associates. "I really believe we are taking the right steps," said Ms. Owens.

Other companies are trying to devise solutions to their failed formal mentoring programs. A few years ago, BearingPoint Inc., the consulting and technology-services company based in McLean, Va., tested a formal mentoring program in which about 500 employees participated. But the pairings weren't that well conceived and within six months it fizzled out, said Natalie McCleaf, BearingPoint's managing director of global human resources.

The company started researching different kinds of programs and recently rolled out a new initiative. Instead of being paired up, employees can access an online kit that provides information on how to select a mentor. The employee identifies his or her goals and objectives, and then finds a participating BearingPoint executive who is a good fit.

"This is a mentoring initiative, as opposed to a formal program," said Ms. McCleaf. "Mentoring has to be something that is encouraged, but not mandated, in order for it to be successful."