Job interviews can be rough under the best of circumstances. They're not helped any when bad interviewers ask questions that take away from the real point of the interview, which is to assess your skills and how well you fit with the rest of the team. The categories that follow are some of the most commonly asked bad interview questions, which might help to prepare you, so you're not caught off guard.
Keep in mind: Your job in the interview is to sell yourself to the interviewer. Your aim is to communicate that you have the skills the team needs and that you can work well with others. You want to talk about how you can make the company money, save money, or save time. When you are asked questions that seem to veer away from those areas, try to bring back the conversation to the issues that matter.
However, no matter what kind of questions you get, keep your opinions about them to yourself. It's not appropriate for you to say something like, "Really? You're going to ask that?" or "What does that have to do with the job?" The only exception to this rule is if the question asks something that could be illegally discriminatory, as described below.
Arcane Technical Facts
- What are the elements of the OSI network model?
- Here's a piece of paper. Implement a doubly-linked list in whatever language you like.
- Name as many options of the ls command as you can.
The questions that most programmers seem to worry about, at least based on the number of books on the topic, are specific technical facts. Books and websites abound telling you how to answer, "Explain polymorphism" or "How do virtual destructors work in C++?"
I fear that many people study these books hoping that it will help in an interview. Yes, it may help you to brush up on certain concepts; for example, if the job requires a technology you haven’t used in a year or two, it makes sense to graze the literature to learn what’s changed. But anyone who thinks that memorizing answers from a book is going to get him a job is fooling himself.
Whatever you answer, don't just give facts. The interviewer may ask you questions off a checklist, but you don't have to answer like it's a test in school. The interviewer should be finding out if you know how to do the work, but if he's not, then help him along.
For example, if the interviewer asks, "What is a reference in C++?" don't answer by parroting, "A reference is a quantity that holds the address of an object but behaves syntactically like that object." You can start with that definition, but then explain why you use references, and how you know when to use a reference and when to use pointers.
For questions that ask for trivia and not working knowledge, such as rattling off all the different printf format specifiers, answer what you can, but don't be afraid to say, "That's all I know, but in situations like this, I turn to (some information source) for the details." Specify where exactly you would look, whether it's a man page, or a well-worn O'Reilly Nutshell book, or php.net's online documentation. Don't just say, "I would Google it." Give specifics of actual sources that you've used before.
If someone asked me to implement a doubly-linked list, I'd explain that I haven't had to write code for that since 1986 and that I'd turn to an already-written implementation online. If I couldn't find an existing library, I might turn to one of the three volumes of Knuth or to the copies of Mastering Algorithms in C or Mastering Algorithms in Perl on my shelf.
- How many windows are there in New York City?
- How many people are using Facebook at 5pm on a Friday?
- How many golf balls would fit in a 747?
- How many gas stations are there in Texas?
Estimation questions are all the rage these days, based on several recent articles, including this glassdoor.com survey, which has been rehashed and repurposed dozens of times in the past few months.
Estimation questions upset people, and that's understandable. Being asked "How many golf balls fit inside a 747?" when you're not interviewing for air transport of golf balls is a waste of time.
For some companies, such as Google, Facebook, and others with huge infrastructures, it makes sense to judge the candidate's ability to estimate absurdly large numbers. Scalability is one of their core competencies. For everyone else, it's a waste of time, even if the interviewer thinks, "It gives me an idea of how the candidate thinks." What the interviewer should probably be asking you is something more grounded in his actual business needs – perhaps estimating server needs for a new website, or estimating project schedules.
If you get one of these estimation questions, go ahead and answer to the best of your ability, but then follow up with discussion of more realistic examples of your estimation skills. You could say, "Based on my rough calculations, I'd estimate 32,500 golf balls could fit," and explain how you got to that conclusion. Then, immediately follow up with, "I'm much better at estimating project schedules. Last year I was part of a five-month project with three other developers, and we shipped it only four days over our initial estimate."
- What song best describes your personality?
- If you were a tree/animal/kitchen utensil, what would you be?
- What was your favorite cartoon as a kid?
- What would you take with you on a desert island?
Even worse than the estimation questions are the fanciful philosophical time-wasters. There's no right answer to these questions, other than whatever the interviewer has in his head, and there's no way to steer it back to reality. At least with estimation questions, you can tie your answer back to something that is useful to the company, but in this case, you're out of luck.
The best you can do is think of an answer, give the response, and then forget about it. Don't dwell on it or waste brain cycles trying to figure if yours was the right answer. You'll never know what the right answer was, and you'll lose focus from talking about the tangible benefits you can bring to the company.
- Why are manhole covers round?
- How would you weigh a 747 without a scale?
- You are in a locked room with only a ball of yarn, an onion bagel, and Volume 3 of Knuth. How do you escape?
These are no better than the philosophical questions. While the interviewer is looking for one correct answer, it's something that you either know or you don't. Like the philosophical questions, give your best answer and then put it out of your mind. You either got it or you didn't and worrying won't make it any better.
If you can follow up your answer with tying it back to reality ("Interestingly enough, I worked on a database project for a bagel bakery back in 2009 using...") then do that.
Questions that get at discriminatory questions
- Your last name is interesting. Is it Polish?
- When did you graduate high school?
- How many kids do you have?
In the United States, it's illegal to discriminate in hiring on many different factors, including sex, ethnicity, religion, and many others. If you're asked questions about any of those topics, it can make things very uncomfortable.
Despite all the blog posts out there that refer to "illegal interview questions," it's not illegal for an interviewer to ask questions about these topics. Quoting from the Equal Employment Opportunity Commission:
Although state and federal equal opportunity laws do not clearly forbid employers from making pre-employment inquiries that relate to, or disproportionately screen out members based on race, color, sex, national origin, religion, or age, such inquiries may be used as evidence of an employer's intent to discriminate unless the questions asked can be justified by some business purpose.
TL;DR: It's not illegal to ask, but it's stupid to do so, because it's just asking for a lawsuit.
So what do you do if you're asked a question that gets at one of these verboten areas? The most important thing is to not assume malicious or inappropriate intent. Nothing is gained by getting combative in the interview. Don't say anything like, "You can't ask that, and I'm going to sue this place."
In general, try to answer the question that they're really asking, without giving away anything that could be used in a discriminatory way. Sometimes they are just asking for information poorly. For instance, if you're asked, "Do you have any children, or are you planning to?" or "What church do you attend?" you could answer, “I don't have any family or outside obligations that would get in the way of my doing the job." If you're asked, "Did you grow up in a Spanish-speaking country?" you can answer with something like, "I speak Spanish fluently."
If you're asked a question that doesn't seem to have any legitimate reason to be asked, like "Are you Chinese?" turn it around and ask the interviewer something like "That question is surprising; what makes you ask?" or "I've never been asked that. Does it relate to the job somehow?" If the interviewer persists, you need to end the line of questioning by saying, "I'd like to get back to talking about my qualifications for the job."
"What is your greatest weakness?"
This is the king of bad interview questions. It's the start of a stupid little game. The interviewer wants to get the candidate to expose something bad about himself, such as, "I have a violent temper if anyone disagrees with me," so that the applicant can be eliminated from contention. The candidate knows this and comes up with a weakness that isn't really a weakness, such as "I work too hard." It's a dance of lies.
The other reason that you might get asked this question is if the interviewer hasn't put much thought into what she's trying to find out. She probably saw it on a list of questions that someone should ask and didn't put any more thought into it than that. It's the same reason that candidates waste space and reader attention with objectives on their resumes: They just heard it was the thing to do without thinking about why.
However you deal with these questions, remember a few overriding principles that apply throughout your interview.
- Don't think of the interview as an interrogation. Treat it as a business meeting with your new boss at your new job that you don't yet have.
- Tell stories, especially of past successes. Stories give details that help convince the interviewer that you're the candidate for the job. This also means you must gauge the interviewer’s response to know when to shut up.
- There are no universal answers. There are 6 million companies in the U.S. and they aren't all alike.
Or perhaps you’re worrying about the flip side of this issue. Did someone ask you to participate in the interview process for a new team member? Read our advice about What To Ask Candidates In Job Interviews.