Last November, veteran nurse Dianne Baker was named acting supervisor for the outpatient cardiac rehabilitation center at a hospital near Philadelphia.

Ms. Baker, whose new duties included managing three other employees, quickly found herself at sea. She wasn't sure how to oversee former peers and stumbled over the paperwork and finances. Monthly financial reports were "like reading gibberish to me," she says. After operations meetings with a hospital executive, she asked colleagues, "What is he talking about?"

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"I'm a clinical expert in what I do, and that doesn't always translate into skills for management," she says. "You have to learn all new skills."

It's an experience all too familiar to new managers. Employers often promote strong individual performers to supervisory roles with little instruction. But people who excel among the rank-and-file don't automatically have the skills or knowledge to manage well.

Companies call it "'on the job' training, but it's really trial by fire," says Robert Kelley, an adjunct management professor at Carnegie Mellon University's Tepper School of Business in Pittsburgh. New managers mostly learn by trial and error, he adds, and find the transition difficult. "They're very ill-prepared for all the routine things that managers do."

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As corporate profits rebound, employers are spending more on training, but most are skimping on help for first-rung managers. An average of just 7% of employers' training budgets was aimed at first-line supervisors in 2003, down from 12% in 2002, according to the most recent data from the American Society for Training & Development. Much of that training goes to help managers comply with workplace rules on issues like sexual harassment, or to teach them financial basics such as budgeting.

That leaves little time for training on "soft skills," such as coaching, leading, disciplining, giving feedback and resolving conflicts. As a result, human-resource consultants say, new managers struggle to strike the right tone with former peers, with some trying too hard to stay one of the gang and others asserting their authority too harshly. New managers are also notoriously inconsistent, confusing staffers with intermittent or conflicting feedback.

Big multinational corporations are more likely to offer comprehensive training than smaller companies, where instruction is hit or miss, consultants say. Among the worst offenders are organizations filled with professionals, such as lawyers, doctors and journalists, who consider themselves masters of their craft first and managers second.

Whatever the field, one of the toughest issues for new managers is supervising former peers. After mechanical engineer Donald Pierce was promoted to supervise a few employees at the National Institute of Standards and Technology several years ago, he had to confront an employee about tardiness. Mr. Pierce was good friends with the man -- they take an annual fishing trip together -- and with others he now managed at the government agency, and he sensed that his employees were watching to see what he would do.

Mr. Pierce hadn't had any coaching on how to handle this kind of tricky situation. He decided to talk to the employee privately, but firmly. "I didn't yell, but I was serious," he says. "I was like, 'I'm calling you in here not to B.S. about outside work stuff'" but about a job issue. "I told him, 'you know, part of my job is to make sure you're doing yours and that you're showing up on time.'"