Why so many job interviewers are terrible

March 8, 2013, 4:26 PM UTC

FORTUNE — What songs best describe your work ethic? How many cows are in Canada? A penguin walks through that door right now wearing a sombrero. What does he say and why is he here?

Those queries come from the Top 25 Oddball Interview Questions for 2013, as compiled by the job hunters’ website Glassdoor. Allegedly, they’re all actual conversational gambits used by corporate interviewers.

You may think such questions could produce useful insights. Or you might see them as off the wall. But are your interview questions any better?

Managers tend to think of interviewing job candidates as “something that’s easy,” says Pamela Skillings, president and chief trainer at Skillful Communications in New York. Believing they’ve reached a career level where they have been magically imbued with the gift of giving a good job interview, such managers wing it and fail to prepare questions that will reveal the best potential employees. All too often, they get a penguin in a sombrero.

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“They end up hiring someone who costs the company a lot” in wasted training time and salary expenses, Skillings says. “You try to fix the mistake you made in the interview process. Then you have to fire the person or move them into a different role, and you have to start over.”

A bad interview “hurts the manager first,” Skillings says. “A bad hire is going to come back to bite you.”

Some managers try to protect themselves with vague questions of the “tell-me-about-yourself” variety. But experts say such prosaic questions produce answers of little use.

Before you sit down with job candidates, “you need a great shopping list” that lays out what you need to know about each applicant for a particular position, says Mel Kleiman, author of Hire Tough, Manage Easy and president of HR consulting firm Humetrics, which is based in Sugar Land, Texas. It’s basic stuff, Kleiman says: “Can you do the job? Can you do the job at the degree of excellence needed? Will you do it? Can you and I live together? If you are hired, can you put up with our culture and [can] we put up with your personality?”

Those aren’t the interview questions, Kleiman says. They’re templates you can use to design questions whose answers will tell you, “Is this person right for the job and is this job right for the person?”

Rather than focusing on eliciting the answers they need, inexperienced interviewers often ask rote questions that “bounce along the surface without getting to know the real person behind the interview hype,” says Paul Falcone, author of 96 Great Interview Questions to Ask Before You Hire. “There’s not much rhyme or reason to their questioning techniques” and they ask the same basic types of questions to all candidates for all positions.

Falcone’s examples of rote questions:

  • Who was your favorite boss, and what would he or she say about you?
  • Which position was your favorite and why?
  • Why do you think you’d want to work here?
  • What questions can I answer for you?

Effective interviewers ask “behavioral” questions, according to Skillings. They use phrases such as, “tell me about a time, give me an example,” she says, because the way a person reacted to a past situation may be an indication of what he or she will do in the future.

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So, “instead of asking ‘Are you a good negotiator?’ it’s better to say, ‘Tell me about a negotiation and how it went.’ Get a real example. Probe for details. Get to the heart of what you need to know,” Skillings says.

Falcone agrees. “We need objective diagnostic indicators of an individual’s probability of succeeding within our organization.” Otherwise, interviewers are “left picking from among people who may sell themselves better than others.”

Falcone’s examples of effective interview questions:

  • Walk me through the progression in your career leading me up to what you do now on a day-to-day basis.
  • What makes you stand out among your peers?
  • What criteria are you using in selecting your next employer, including the industries you’re considering, company criteria, and the roles and titles that you’re pursuing?
  • If you were to accept a position with us today, how would you describe that to a prospective employer five years from now in terms of your career development and longer-term goals?

Ask questions that “reveal a candidate’s level of career introspection,” Falcone says. “Do they know what they want? Can they articulate their career history in a clear and compelling manner?”

During the interview, really listen to the candidate, Kleiman says. “You’ll never learn anything while you’re talking.”

If hiring people isn’t your main job, don’t be afraid to ask for help, recommends Skillings, who teaches workshops and online courses on conducting interviews. “We see a little bit of attitude from managers” at the beginning of training, she says. “`I don’t need this, I know how the deal works.’ By the end, they realize they didn’t know things, or were rusty.”