1. "So, what's your background?" Interviewers shouldn't need to ask this question, because they should have reviewed the candidate's résumé before the interview. When an interviewer shows up unprepared, they won't be able to conduct a strong interview, and will signal to the candidate that they don't put the same value on building a great team that a truly strong manager does.
2. "What is your biggest weakness?" This question has appeared in so many interview preparation books that it's become a cliché at this point, with nearly every interviewee prepared with a canned answer for it. It rarely elicits useful information, and what's more, a good interviewer will be able to make her own judgments about a candidate's weakness. It's hardly helpful to hear "I work too much," "I'm a perfectionist," or the other disingenuous responses candidates are taught to give.
3. "What's your salary history?" Unless the interviewer is prepared to offer complete transparency when it comes to the company's salary ranges (which most employers aren't), this is an unfair question that makes most candidates uncomfortable. Furthermore, it's unnecessary. You should pay candidates based on the value of their work to your company; what previous employers paid them isn't relevant. And yes, sometimes lazy employers like to use salary history as a shorthand to determining a candidate's worth, but good companies can figure that out on their own—without expecting the candidate to answer questions that, frankly, are no one's business but hers and her accountant's.
4. "Do you think you can handle this workload?" Asking a candidate a hypothetical question isn't likely to get you useful information, and most people are smart enough to say "yes" to questions like this. Instead, better questions probe into how the candidate actually did act in the past, such as asking, "How much volume did you have to handle in your last job? How did you stay on top of it all? Tell me about a time when the volume was at its peak and how you handled it." These questions probe into how the candidate really does operate, not just how she says she will in the future.
5. "If you were a tree, what kind of tree would you be?" Also known as "What kind of animal are you most like?" and "What would I find in your refrigerator right now?" Goofy questions like these rarely elicit useful information, and they'll alienate most candidates. After all, the strongest candidates will want to spend the interview talking about their background, the job you have open, and what they might bring to it. Goofy questions will annoy most good candidates and make them question why you're wasting their time—and plenty will decide they're not a good fit with a hiring manager who hires this way.
6. "If I offered you the job, would you accept it?" Few candidates are going to answer "no" to this question, and the real answer is usually "it depends on how much the offer is for." This question doesn't garner the interviewer any real information—but does make most candidates uncomfortable.
7. "What does your husband do?" or, "What church do you go to?" or "Do you have kids?" Personal questions like these are inappropriate for interviews, which should focus on the candidate's ability to do the job. And moreover, while the questions themselves aren't illegal to ask, making a hiring decision based on the answers is—so you can't consider the responses, and most candidates with knowledge of the law will wonder if you're asking with the intent to illegally discriminate. Steer clear of personal questions and stick to the candidate's fit for the job.
Instead of asking ineffective questions like these, interviewers should spend their time probing into the candidate's qualifications—asking in-depth questions about how they've operated in the past, talking over challenges they'll face in this position and how they've responded to similar situations, giving them opportunities to simulate the work, and helping them get a better understanding of the job they would be signing up for.
Alison Green writes the popular Ask a Manager blog, where she dispenses advice on career, job search, and management issues. She's also the co-author of Managing to Change the World: The Nonprofit Manager's Guide to Getting Results, and former chief of staff of a successful nonprofit organization, where she oversaw day-to-day staff management, hiring, firing, and employee development.