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We’re Bad at Interviewing Developers (and How to Fix It) – Interview with Kerri Miller

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In this interview with Kerri Miller, Lead Software Engineer at LivingSocial, we discuss how to hire and interview developers. We typically don’t get trained on interviewing and we’ve all experienced the haphazard approaches of those new to it – poor organization, repeated questions, fizz-buzz… Kerri tells us how to run interview days, the types of questions to ask, how else we can evaluate candidates and what to do after the interview. For more tips, Kerri writes about software development and hiring on her blog.

Content and Timings

  • Introduction (0:00)
  • What’s Broken with Developer Hiring? (0:44)
  • How to Structure and Run Interview Day (1:53)
  • Good Types of Questions (2:54)
  • Beyond the Interview – How Else to Evaluate Developers (4:00)
  • After the Interview – Making the Hiring Decision (5:56)
  • Measuring and Improving Your Hiring (9:12)
  • Common Developer Hiring Mistakes (11:23)



Kerri Miller is lead software engineer at LivingSocial. She is also a RailsBridge instructor and frequent conference speaker. She talks about software development and hiring, including the talk, ‘We’re Bad at Interviewing and How to Fix It’. Kerri, thank you so much for taking time to join us today. Do you have a bit more to share about yourself?

I am actually in fact a lead software engineer at LivingSocial. Part of that is working with junior developers, or more junior developers, leading software teams and projects, and I also do a fair bit of work in our engineering culture team, so doing things like how do we propagate a good culture for code reviews, post-mortems, and hiring.

“You want them leaving the interview process regretful that they didn’t get hired, not resentful that they didn’t get hired”

What’s Broken with Developer Hiring?

What do you think is broken with the current way a lot of companies hire and interview?

We don’t do a really good job of hiring with intent. We decide that we need more people, but we don’t do a really good job of figuring out what we need those people to actually do, and who we actually need to hire. I like to think of my software teams as little ecosystems, little, tiny arcologies that exist in a bottle. They’re not entirely a closed environment, and, like any ecosystem, anytime you introduce anything new to that realm, there’s going to be changes. There’s going to be impacts.

Any time you hire somebody, you’re changing that ecosystem. You’re introducing a new species, or a new variable to things and it’s going to change. Thinking about what you want to change means that you have to have laid that groundwork to understand where you are at the moment. A lot of teams and companies don’t do a really great job of understanding that. They’re just simply, “We need more bodies. Let’s hire bodies.” They don’t go into these things with a conscious sense of where they are and what they need, and how the future’s going to change by adding more people.

How to Structure and Run Interview Day

Let’s talk about interview day. How should we structure it, and what are some key aspects you need to get right?

You need to go into it having a plan, and that plan starts with knowing what questions you’re going to ask and why. Understanding that every question you ask that a candidate can’t answer, or every step of that process is an opportunity for a candidate to filter themselves out of that process, it’s a point for you to get information to make that final decision. I think it’s really important that you take a look at what that plan is going to be. If you have, say, three people, and you’re hiring for a front-end developer, you should have one person ask about JavaScript. You should have one person ask about, perhaps, browser interaction, or working with designers, or what have you. Just splitting up that interview so that you’re not asking the same questions over and over again, you’re really able to get really solid signal on a person’s skill sets, what they’re comfortable with, and what their concerns are. What kinds of decisions are they making?

Good Types of Questions

What are good kinds of questions that we should be asking?

Well, I’m not a big fan of whiteboarding, because I think that’s something that we just automatically do, and we don’t think about, “Well, what questions are we trying to answer by asking a candidate to solve a problem?” Are we dinging people for trivia questions, for not remembering, “Oh, I need this third option flag, or an obscure method from a core library.” Instead, I really want to focus on questions that are asking about decisions that they’ve made, what choices have they made, and what choices would they make again in the future? Are they reflective about mistakes that they’ve made? Are candidates looking for opportunities to improve, and how do they actually go about it? Do they make plans for themselves, like how they would improve a certain skill set, whether that be a technical skill set or a more soft skill set, for example, management, or project shepherding for example. Those are the kinds of questions that I think really get you at the heart of not necessarily what somebody knows, but what they’re capable of.

Beyond the Interview – How Else to Evaluate Developers

You’re a proponent of evaluating candidates in other ways than just an interview. How else should we be finding out more about potential employees?

I’m a really big fan of pairing on projects, like actually working with somebody. It doesn’t have to be a formal or traditional pair programming situation with one computer and two people, talking through the technical choices that they would be making as they programmed on something. At LivingSocial, we do a code challenge like a lot of companies do, using that as, then, a launching pad to have a discussion with a candidate to say, “You solved the problem using this technique. Why didn’t you choose this other technique? Why did you choose this one? How would you do it better? What if we sat down and refactored?” That’s one really good way to really get the heart of why are they making the decisions they’ve made? Not just did they make this choice because they didn’t know, or are ignorant, or did they make this choice because they had a certain belief about what the requirements of a given project were? That’s one way to do it.

Other ways you can be finding out more about potential employees … I’m a really big fan of asking the employee to explain something to me, or teach something to me. In the past we’ve done this with simply just saying, “You can teach me anything, something that I don’t know, and preferably is non-technical.” How well do they communicate about something that they’re a local expert in but they’re intended audience is not? Could they then go off and go and learn a new framework, or go have a meeting with, perhaps, a stakeholder, or a client, and come back and explain what the actual requirements are to me, to distill down what I need to know and communicate that well? Communication is such a big part of what we do in this job, and so testing for that essential skill in a really clear and explicit way can be really useful and get you a really good signal about who that candidate is and how they’re going to fit into your organization.

“We don’t do a really good job of hiring with intent”

After the Interview – Making the Hiring Decision

After the interview, what are key things that employers should be doing?

I think it’s really important that we don’t just say, “We’re going to get back to you,” but to say, “We will get back to you by Thursday, end of day.” Then, if you can’t make your decision within those three or four days, communicating that to the candidate so they have expectations that you can meet, because it’s not just good for the candidate, it’s good for you as a company to have that discipline, because you want people to, whether you hire someone or not, you want them leaving the interview process regretful that they didn’t get hired, not resentful that they didn’t get hired. Being professional and upfront and just friendly and encouraging about the entire process is great.

I try always to make sure that, if we can’t hire somebody for whatever reason, we make sure that we give them constructive advice or feedback afterwards, or at least make that available. If you did like somebody, if it came down to either Joe or Mary, and you hire one or the other, keep that person on file, and follow up with them in a few months to see how are they doing, what’s going on? “Hey, we have an open position, would you like to re-apply, or would you like us to consider you for that?” That gets into part of how you keep metrics on things as well, because if you didn’t hire somebody, figure out why you didn’t hire them and then follow up and see, are they actually doing that work, and did we hire the … Not necessarily the wrong person, but did our process let us down? If you assume that somebody didn’t know anything about, say, SQL, and now they’ve gone on to work on a SQL-heavy project, for example, what in our process missed that step?

“It’s really hard to look at who you hire and decide that you have a good or bad process. But you can look at who you don’t hire.”

Great, so we talked about having a plan as part of the hiring process, what’s a good process to follow to make a hiring decision?

When you split up the interview topics, the questions you’re going to ask, and you’re going to consistently ask all of your candidates, it feels a little bit like reading a script, but it really lets you compare apples to apples as much as possible. Once you’re done with your little section of the interview, you should immediately go back to your desk and not get back to work but write down what your impressions were. What were the pros and cons, the bullet points, and find something good about the candidate and something not-so-good about the candidate, something that you with they did have. Doing that in that moment and passing that back to a central person so as not to … Don’t pass it back to a group, pass it back to a central person, whether that be an HR, or the hiring manager, to collect that, so you’re not coloring the impressions of other people.

When you get back into that room with everybody else, whether it’s virtual or real, to really discuss your opinions, you’ve got your opinions of the moment and you can’t be swayed by the impressions of somebody else. For example, if you were supposed to interview them about JavaScript, and the senior JavaScript person, who’s got twenty years of experience in JavaScript, just really did not like that person, how would that color your opinion if you had to give your opinion in that moment? If you wrote it down previously, no, this person really is good at JavaScript, then you’ve captured that honestly and you can really give honest feedback about what that person’s qualities are and what their strengths are without being colored by other people in that discussion.

Measuring and Improving Your Hiring

You hinted at this earlier, but a key part of your approach to hiring is measuring the process to improve it. How could we go about measuring the effectiveness of our hiring?

It’s very seldom that we ever hire anybody bad. When you hear horror stories about hiring, it’s always somebody else’s team that hired that one jerk, or that one idiot, so it’s really hard to quantify, because now we know that person, and we’ve worked with them, and we understand their strengths and their weaknesses. It’s really hard to look at who you hire and decide that you have a good or bad process. You can look at who you don’t hire. You can look at that in terms of what were the false negatives? Did we bounce this person out of the process for a specific reason and then it turns out that that reason wasn’t good based on where they ended up going to work?

It’s really easy to LinkedIn stalk people, and peak into their GitHub profiles if they’re doing that sort of work, to see what they’re doing a few months later. It can be really useful to, four, or five, six months down the road, go back and look at the candidates that you passed over and see what they’re doing to understand, if you keep records of the questions that you ask, and the reasons why you maybe didn’t hire somebody, to see if those reasons are still valid.

Other metrics that I think are really, really important to an organization are understanding what your pipeline for candidates consists of. At each step, you have a certain amount of leakage, because people just simply don’t make it through the process or they abandon the process, they disappear. How many people are you losing at each step, and is there one step that you’re losing a lot of people at? Maybe you need to refine that step, remove it, or move it earlier or later in the process based on what your organizational needs are. I think it’s also important to look at who you’re losing as well. Are you losing junior developers at a step that you really don’t want to be losing them at? Are you losing more diverse candidates? Are more women abandoning your process at a certain step than men are, and understanding, or questioning at least, your process to see, is that a problem? Can we fix it? How do we fix it?

“You should immediately go back to your desk, and not get back to work, but write down what your impressions were”

Common Developer Hiring Mistakes

What are some common mistakes you see companies making when hiring developers?

Some of the more common mistakes are hiring from our friend networks. I think that the friend network is such an important part of how we get jobs, but it also tends to reinforce our monocultures a little bit. We tend to be friends with people who are mostly like us, and so those are the people that we’re going to be recommending, and so those are the ones that get hired more often. When I was mentioning earlier how the team is an ecosystem, it’s important to have some diversity there, and not just the diversity we talk about in terms of gender or ethnicity or race, but age, class, looking at people’s technical backgrounds, do they come out of CS programs versus being self taught or a boot camp?

Industry backgrounds, did they work in, perhaps, consumer electronics testing before they became an SDET at Microsoft? Were they at startups versus large enterprise companies, or somewhere in between? All those pieces of diversity are going to be influential and improve the health of the ecosystem of your team, and so those friend networks are important for getting candidates in the door, but understanding that that sometimes is going to lead to a certain amount of self-selection for candidates.

You have to, like in soccer, they say, “Run to where the ball will be, rather than where the ball is.” If you have those early conversations about who you need to hire, and what you want to look for, what sort of energy and person do you want to add to your team, to influence it into a good direction? And then go to those people, find them, whether it be through meet ups, or user groups, or extending your extended network, not just your immediate friend network.

Are there any other resources you can recommend for those looking to improve how they hire developers?

Looking at the different boot camps you’re doing, and how they’re talking to their students, as well as to their sponsoring companies, or the companies that are hiring. I’m a really big proponent of hiring more junior developers, because no one is ever going to know our exact technology stack and our exact way of working, we always have to teach people, so looking at what those boot camps are doing, and how they’re talking about the industry, because they’re trying to set people up for success over the next five years. There’s a lot of wisdom. They’re spending a lot time to gather wisdom that they can relate to us about who we should be hiring over the next five years, and what skills we should think are important.

Finally, I tell everybody this, go take a relationship skills class. Although they’re sold as being aimed at couples, a lot of that is really about listening to other people and understanding what their concerns are. Once you can start to build those sorts of skills for understanding the perspectives of other people, just generally improves everything about your hiring process, and your team, and how you work with each other.

Kerri, thank you so much for joining us today.

I’m really excited about this topic. I’m glad to see more and more people talking about it. There’s no one size fits all solution. We all face some really unique problems, but there are some commonalities.