Dear M.O.: You’re right to be skeptical that your boss, or for that matter anyone else, will abide by the dates-and-titles-only rule. It seems that many people, when asked for a reference, can’t resist the urge to add an editorial comment or two—and the less the person thinks of you, the more likely he or she is to offer an opinion. “About 50% of the people we contact say something negative,” observes Jeff Shane, head of reference-checking service Allison & Taylor. “And that holds true even in companies that have a formal dates-and-titles-only policy.”

A few recent examples: Queried about a job candidate’s strengths and weaknesses, one reference said, “Weaknesses seem to stick in my mind. I’d really have to think about whether he had any strengths.” Ouch. Asked to rate an ex-employee’s skills on a scale of 1 to 10, his former boss replied, “Can I give a negative number?” Another supervisor, asked about someone’s integrity, replied, “I doubt she had any.” Then there’s the ever-popular, “Hold on, let me pull out his legal file and see what I’m allowed to tell you.”

Unfortunately, Shane notes, most employers will contact your boss for a reference even if you don’t list him or her—unless you ask them not to. “It’s perfectly acceptable to explain to an interviewer that your current supervisor doesn’t know about your job hunt and you’d prefer to keep it that way, at least for now,” he says.

If possible, provide contact information for a manager you reported to earlier in your career, and who liked your work. Just be sure to alert him or her in advance that prospective employers might be calling. Since it may have been a while since you worked together, you can also take the opportunity to remind your old boss of why you worked so well together.

In addition, Shane says most employers will accept 4 other types of references:

A manager (besides your boss) who knows you. Especially if you’ve been at your current company for more than a year or two, there is probably someone at your supervisor’s rank, or higher, who has some knowledge of your work. Try to think of “someone who you think would offer positive, or at least neutral, comments about you,” says Shane. Since it should also be someone you can trust not to spill the beans about your job hunt to your boss, this is one situation where having a mentor higher up on the organization chart can really come in handy.

Peers or clients, or one of each. Think back to any project where you did a stellar job, and suggest an interviewer contact the other people involved who can “personally attest to your skills and expertise,” says Shane. These folks have the advantage of knowing some details of your performance that your boss may not even be aware of, which can make their remarks that much more convincing.

Subordinates. Particularly if you’d have people reporting to you in the new position, anyone reporting to you now should be able to offer a valuable perspective. “Often they really know more about your day-to-day performance than your boss does,” notes Shane. Ideally, they like you better, too.

The human resources department. Job hunters often overlook them, but as a company’s official “people experts,” HR staffers carry a lot of credibility with employers checking references. “They’re also most likely to follow corporate policy and limit their commentary about you,” Shane notes.

“Especially if you’re asking employers not to contact your boss, it’s critical to select people who will present you and your achievements in the best possible light,” he adds—even if that means having to coach them a little, or at least jog their memories, in advance. Good luck.

Talkback: Have you ever given references other than your boss to a prospective employer? Whom did you choose, and how did it work out? Leave a comment below.