How to not suck at a technical interview*
This is partially a rant and partially an honest to goodness attempt to raise the overall bar in our industry. Given that there are about 4 people who read this blog the latter is mostly a pipe dream but still.
I have been involved in the interview process at my last couple companies. In the last few years I have picked up on a few things that I see consistently in interviewees. My hope is to distill these things in this post and try to offer some insight into what we, as interviewers, think of these traits and what we would really like to see from an interviewee.
Ok enough altruism about helping the industry. Bottom line is MOST applicants in the software development industry suck. Yeah yeah yeah, bitch all you want about my exaggerations and oversimplifications. The thing is, it’s true. Interviewing is painful. It is the exception not the rule that I find someone who is even worth more than 5 minutes of my time.
For a while I honestly thought I was a bad interviewer and that my questions were too complicated or convoluted to be understood. I still don’t think I am the best interviewer by any means. I have however changed my approach to asking questions and try to work with the interviewee to get them talking and make them comfortable. But it isn’t my style that is broken it is the overall level of skill in the industry that is broken.
I am not talking about personality quirks, nervousness, or any other interview related issues. Look, I get it, programmers are a strange bunch. It is expected that you are going to interview odd balls, eccentrics, type A assholes whatever. I can deal with that. One piece of interviewing that I like to think I am ok at is filtering out these types of things and trying to identify the applicants true skill set. Sure, personality is part of an interview and certainly a vital part to team chemistry. I take a person’s personality traits very seriously in determining my opinion of the applicant. But, none of that matters if they don’t have the fundamental skill set needed.
So here are a few things I see repeatedly during interviews.
1. Stretching your skill set: Ok, I get this one. I understand how it works, you need to throw the buzzwords on the resume to get your foot in the door. If you copy and paste a laundry list of the current buzzwords on your resume you better be prepared to answer questions about ANY of the buzzwords on your resume. Don’t tell me you are “an expert in Entity Framework and LinqToSQL” and not expect me to ask you a question about it. If you can’t hold your own in a discussion about a technology don’t put it on your resume. Also, choose the nouns you use to clarify your skill level carefully. If you say you are an “expert” at something then I am going to drill you with deep technical questions. If you are an “expert” you better be able to teach a class on the technology. Don’t be afraid to say you are simply proficient or even that you are a novice. This sets my expectations properly so I can formulate questions. No one is an expert at everything, I don’t expect that. So when I see someone that is an “expert” at every current buzzword I get highly suspicious.
2. Few details about current position: I almost always lead with something like “tell me what you have been working on lately.” One, I am trying to ease the nerves and let the person talk about a subject they should be intimately familiar with. Inevitably I get some high level response with a bunch of superfluous buzz words and very little technical meat. This doesn’t help! If you can’t explain your current position, in detail, I am already out on you. Out of any of the questions I am going to ask this is by far the simplest. Just tell me what you are working on. Talk to me like I am a co-worker and we are chatting in the hallway at work. I am a nerd too, I understand geek speak, I can fill in gaps. Don’t fear losing me or giving me to0 much detail. A solid response to this question frames the entire rest of the interview. It gives me content to build on. It gives me areas to press you on. But, most importantly it give me insight into how you think.
I really can’t stress that last sentence enough. It will be a recurring theme in this post.
3. Unwillingness to say “I don’t know.” Arggggghhh seriously, this one gives me a headache more than anything else. For god’s sake just say “You know, I am not sure I know the answer to that question.” So many people just try to talk themselves out of a corner or give some vague answer hoping I will buy it. Really? Do you really think, if I ask you a question, that I don’t know the answer? If ask you something I damn well know the answer and I expect you to either give a correct answer or tell me you don’t know. BS’ing the answer or trying to weasel out of the question just pisses me off. Like I said, Arrrgggghhhh. Again, as I said, I have no expectation that people will be experts in everything. I am fine with you admitting you don’t know. Even if the question is related to something on your resume and you don’t know. I would much rather you admit you don’t know then try to fake it. I will often ask questions that I fully expect the person not know the answer to. The reason for this is two fold. One, I want to see if you will admit your lack of understanding and two I want to see how you would go about finding the answer. In almost every programming job you are going to work on problems that you don’t know how to solve, what I want to know is how do you go about finding the answer. If you don’t know the answer to the question tell me you don’t know and add something about how you would go about finding the answer. Would you Google it with Bing. Would you scour blogs, forums, pick a coworkers brain, fire up reflector, read the SDK. Whatever it is explain to me how you would go about it.
4. Not enough use of the whiteboard. This one sounds weird to most I think but it seriously makes a difference. In every single interview I have done the room we are interviewing in has a whiteboard. USE IT. Not just use it but don’t be afraid to jump up and go for it. Every good programming problem requires a white board at some point. We use them daily in our jobs but for some reason we just don’t feel comfortable using them in an interview. I fully expect you to use a white board to solve hard problems in the day to day job so why not use it in the interview. More than anything, watching some one work through a problem on the whiteboard shows me how they think. Seriously, next time a co-worker jumps up to use a whiteboard pay attention to how they organize information on the board. How do they represent different conceptual aspects? How do they move through the flow of information? You can learn a lot things from how someone uses the whiteboard.
5. Thinking too procedurally. If you get nothing else from this rant please understand this. The number one issue I come across with applicants is a fundamental flaw in their problem solving approach. Too often people suffer from tunnel vision when it comes to solving problems. They find a solution to their problem and don’t take the time to understand why the particular solution works or what, conceptually, they have accomplished. I call this “thinking procedurally” because people seem to understand how to get from point A to point B but throw in even the smallest speed bump and they completely fall apart. They understand the “procedure” to get the work done but they fail to see the larger concept in play. This is the number one issue that causes me to end an interview or give a thumbs down on an applicant. This goes back to the previous two points. I don’t expect you to know everything, be willing to say I don’t know, but if the question sounds like something familiar work your way through the answer, out loud. Talk me through your thinking. Explain to me where you are getting your background from and why you feel it might be similar to X. Use the whiteboard to draw it out (remember your high school math teacher “show your work!”). This is eye opening for me. Listening to you work through the problem and explaining how you would approach it shows me if you truly understand the concepts behind the solution or if you have tunnel vision and can’t see the forest for the trees.
Ok I will wrap up my rant now. A few key takeaways if you made it this far.
1. Expect questions about ANYTHING on your resume. If you don’t know it, even if you did long ago but have since forgotten it, take it off your resume.
2. Give me something to go on. Tell me about your recent work, in detail. Tell me why you did things a certain way. Explain the challenges you faced. Explain what worked. Explain what didn’t.
3. Recognize your shortcomings and be honest about them. Explain how you would work to find the answer. Tell me what resources you use to solve these types of problems. What is your workflow? If it sounds sort of like something you are familiar with talk through it. Give me an insight into your thought process.
4. Use all the tools you have at your disposal. Whiteboards are readily available during an interview. Use it. Draw it out, organize your thoughts on the board. Don’t be afraid to scribble, erase, cross out or generally make a mess of the board (you should see mine right now)
5. Think outside the box. Ok that cliché makes me vomit but in all seriousness understand the concepts. If you don’t understand why your solution is actually working, spend time on it. Use reflector, step through the framework source, do whatever it takes for you to understand the fundamentals happening under the hood to solve your problem.
Feel free to give me feedback on this. Am I being too harsh? Am I a dick? (I already know the answer to that one) Do you totally disagree? Praise, flame, bash whatever I am open to it.
*NOTE: This is a personal blog. The opinions expressed here represent my own and not those of my employer.