Interviewing — What to ask during an Interview

Twitter Summary:  The questions you pose to interviewing candidates reveals if your job is interesting or boring.

The questions you ask and your assessment of the candidates answers comprise the core of the interview.  More importantly, excellent candidates will be paying attention to you and will be assessing you just as much as you are assessing them. If the questions you ask are the same the candidate has heard in other interviews, seen in interviewing  manuals, or from another interviewer that day, they will have a clue that your interviews are not organized, your questions aren’t relevant, and that you may not be capable of capturing the depth and breadth of their capabilities.

Great interview questions have the following qualities:


  • The problems you ask them to solve should either be ones that you are familiar with or are currently trying to solve yourself. This gives the candidate a clear indication of the type of work they will be asked to perform.  This also gives the interviewer the ability to assess how the candidate would solve a problem that is pressing for the organization right now.
  • If you are interviewing a software engineer for a kernel development position, ask them to code a scheduler and talk about memory allocation.
  • If the candidate is interviewing for a social networking site, ask the candidate to generate  code to generate a user to user similarity score.
  • If the candidate is interviewing for a marketing position, ask them how they would evaluate marketing options for your current product.
  • Don’t ask a “textbook” questions. — For software engineers, this means asking them to implement “atoi()”. For anyone it would mean questions like: “What is your greatest strength?” Your questions should be open enough that the candidate reveals their strengths in the process of describing another problem they solved.

Expandable in depth and breadth

  • The questions you ask should be expandable in either breadth or depth. For software engineers, this would mean asking them to take their solution and and scaling to handle millions of users or machines, or alternately asking them to change their solution to handle multiple, media and content data types. For product or marketing candidates, you could ask them how they would modify the programs or projects to deal with if you wanted to handle a larger diversity of customer groups or a broader product line.
  • Don’t ask questions with only one right/wrong answer. Asking questions that have only one correct answer is problematic as it doesn’t give the candidate the opportunity to discuss trade offs in choosing and decision making. In the end, you are hiring people to make judgment calls, and are not hiring a computer to give you a rote answer


  • Present only the basics of the problem.  The interview should be a dialogue,  and interviewers should intentionally give less information then the candidate needs to solve the problem. This will get require them to ask you clarifying questions and give you insight as to how they approach their problem solving.
  • Don’t spend all your time talking. If you spend most of the time talking you are not getting the information from the candidate you need to make your decision. You can spend more time talking with the candidate after they have answered your question, and especially if they are hired.

Great inteview questions make your job as an interviewer easier . A great set of interview questions will allow you to understand how the candidate would solve the problems you need to solve in your company, how the candidate deals with challenges as the problem expands, and how they communicate and ask for more information in answering the question.  It also tells the candidate about what problems they can expect to be solving and if the role is a match for what they want to do.

2 thoughts on “Interviewing — What to ask during an Interview”

  1. Good advice here, Ruben.

    I see you mentioned expanding in depth during the interview. That is closest to my personal style of interviewing.

    I usually am looking for enthusiasm for a problem, depth of knowledge on that problem, and a willingness to admit the limits to their knowledge. My strategy is to keep asking probing questions about an area of their previous work, going deeper and deeper, asking them to express why it is important, what they tried, and what they could also have tried.

    Ideally, not only does the candidate infect you with their enthusiasm for the problem, but they teach you something.

    At least in fast-paced software companies, I think these characteristics best determine someone’s likelihood of success. I think it selects for people that can get things done quickly using small teams.

    That being said, interviewing is difficult and full of false positives and negatives. Companies like Amazon and Google bias their selection criteria to encourage false negatives — deeming them less risky than false positives — but that sadly does prevent many good people from getting through the door.

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