Interviewing Developers: triggers, part III

The series:
Interviewing Developers
Interviewing Developers: triggers, part I
Interviewing Developers: triggers, part II
Interviewing Developers: triggers, part III

This post also appears in my other blog.

In the two previous posts I focused on certain behaviors of an interviewee, which may indicate problems with their ability to become a good developer in my team. I covered quite a lot of such aspects that push me towards saying "no" and now it's time to show that I can be positive as well. Positive triggers also help conduct an interview, although rarely shorten it, because they make you eager to speak more to the person. In this post I will list some things that make a good impression on an interviewer, explaining why they are good and thus showing what I look for in potential hires.

Candidate: "If you're interested, I'd like to explain the broader context of my previous job / project / task"

Just basic politeness and showing awareness of the fact that the interviewer may have their own plan and time limits change a lot. However, combined with a person' willingness to share his or her specific past experience it is even more powerful. In many cases an interviewer has to spend a lot of energy to get a reasonable picture of the candidate's background and has few options other than squeezing the bits of information out of the person, so one who offers a clear explanation themselves makes a head start. This positive impression may be further amplified with occasional dives into technical details - for example, down to a brief explanation of a class hierarchy - because this likely indicates both an ability to communicate efficiently and a desire to dig into things and understand them. Finally, note the initiative - sometimes it might be the most important aspect of a future employee - it means they have ideas and fuel to make them happen and your organization will only have to stir them in the right direction.

Candidate: "So we stick that thing into that stuff and …"

This one may sound unprofessional and stupid, but trust me, an ability to explain complex technical constructs using the simplest common language terms (yes, I qualify "stuff" for a term) usually indicates that the person does understand the solution being explained very deeply. Of course, whether you understand what they are telling or not makes a lot of difference and I speak only of the case when that explanation is comprehensible. If it is, you will likely find that it is easy to discuss both the edge cases of the same problem and similar but less familiar issues with the developer. That happens because a person using less formal terms in their speech has already internalized the knowledge being communicated - not just remembered some bits about it - and can play with his or her mental model to adjust and adapt it for other scenarios. This trait of a powerful mind is something that you would terribly like your teammates - especially, developers - to have.

Candidate: "Polymorphism is <reasonable explanation>. Imagine we have a base class called Person…"

Bless the people who provide examples for abstract ideas without being asked directly! Examples help every party involved in communication understand the topic better and spot new questions and ideas. While this merely makes the task of answering an interview question easier to do right, the real value is that the person shows that they are able to see the implications of an idea and view it from different angles. A developer who quickly comes up with examples and tries to view a problem or idea in concrete figures usually thinks realistically and understands the context better. Such a person quickly grasps the real world problems that a piece of software tries to fix and can transfer this understanding to their colleagues. As for an interview, they try to make it easier for you through their usage of examples and this alone deserves some respect.

Candidate: "We were using ASP MVC 2, which is kind of old, so I decided to learn Node.js and built a personal web-site / game / whatever with it"

Here I barely need to explain anything: desire to learn and develop on one's own is what makes great professionals. They also don't blame their boss or organization for not giving them an opportunity to learn new things or work with the hottest new technologies - they simply learn whatever they find appropriate when they feel a desire to do so. On the other side, any developer may occasionally get a bit tired with their day job and issues associated with it. A person with a positive attitude feeling their own responsibility for their growth will be able to help themselves through such uneasiness by means of a personal project. It is true that such a side activity may distract someone from their job, but the stakes are high it would rather improve the way the developer attends to their duty giving them extra energy and ability to bring new ideas from the outside world.

This is far from an extensive list of positive interview triggers and there are dozens of things that will make an interviewer like a candidate. Still, I will stop right here, because the things said are enough to give a good indication of what I value when sitting on the hiring side. I must have highlighted this a thousand times, but any hiring decision is based on a lot of factors and no single one of the triggers that I mention should be treated as a basis for yes or no. Still if you have a collection of such triggers in mind they may help a lot navigating you through the process of acquiring a new team member.

An interview is about finding a great person to close a gap in your team, so it is important to note both positive and negative edges of the candidate's personality. The goal is to check whether the candidate is a good fit for the open position, the team and your company's culture - that's why I pay that much attention to the communication abilities and personal traits. Of course, the most important purpose of the interviewing process is to avoid hiring the wrong person - hence the relatively large number of negative triggers in the previous posts versus few positive ones in this one. At the same time, noticing the good aspects is also important - especially when these show that after being hired the candidate will keep growing professionally, help others and improve the way they and their new team do the job.

In conclusion of this short series I wish you good interviews - on both sides of the process - and welcome you to share the bits that help you learn more from them!

Inerviewing Developers: triggers, part II

The series:
Interviewing Developers
Interviewing Developers: triggers, part I
Interviewing Developers: triggers, part II
Interviewing Developers: triggers, part III

This post also appears in my other blog.

Last time we looked into several responses that I don’t like to hear during an interview. In this post I will add more examples of candidates’ phrases, which usually indicate weak potential for becoming a worthy team member. Next time, to finish on a good note, I will switch to positive interview triggers, but today let’s keep a bit negative.

Candidate: “I’m tired of writing code. I want to be an architect in your team.”

The funniest thing about this is that I usually hear it from 23–24 years old guys, who have at most a couple years of commercial development experience. It is clear that a candidate with this kind of background is hardly fit for a software architect’s position, but it is also difficult to consider them as a developer because they admit they don’t want to do programming anymore. What’s worse, I believe there are few (if any) good architects who don’t wish they could spend more time coding. Somehow the love for programming comes together with good software design skills and the lack of it means one can’t go far on the technical side of the software development world. The simplest rule here is: never hire for a knowledge-based position someone who doesn’t like its core — they will likely be both inefficient and dissatisfied.

Candidate: “That wasn’t my responsibility”

Usually this comes in response to questions like “Why did your team chose to implement X and not Y?” and “Why did you use that framework instead of this one?” If we speak of junior and mid-level developers we indeed must assume that someone else was in charge of making both product and technical decisions, but it is also true that good developers usually care enough about their work and team. This means they do question the decisions made by the team or the company and try to understand the reasoning behind them instead of blindly doing what they are told. It is also common for them to say “we” about the team — even after they left it — and assume some responsibility for its results. If a person does otherwise, it may indicate a lack of curiosity and ambition, both of which are crucial to becoming an effective team-player and growing one’s skills with time.
Candidate: “I was good but the other developer made incorrect decisions and so we failed”
This one is a refined version of unwillingness to take any responsibility — particularly, for failures. I bet, when asked about the reasons behind one of their successful projects that same person will claim full credit for that success. The problem is that such a person is likely a poor team-player. Clearly separating oneself from their team instead of saying “we” tells a lot about the person’s ability to make the team more effective, collaborate and help others. I definitely don’t want to hire someone who will do poor job and then blame the whole world in their failure — such people learn little, don’t work very hard and thus rarely succeed. Moreover, blaming others doesn’t make you look reliable and trustworthy — even outside the interviews.

Interviewer: “Which of your recent achievements make you feel proud?”
Candidate: “There wasn’t anything like that — just common work.”

While treating this response in a strictly negative way might feel too much, it is nevertheless very informative. Even with purely routine work a good employee will discover a way to optimize his day-to-day duties and will feel proud of doing so. The same way, even people who truly believe that they are inferior to others and the results of their work are flawed will likely find something to be proud of if they are willing to assess their achievements. Conversely, candidate’s inability to identify something worthy among their results means they are unprofessional, because a professional always reflects on what they do, looks for ways to improve that and definitely has a thing or two to name as their valuable accomplishments. You don’t want to deal with someone who shows little initiative and lacks a purpose, do you?

In these two posts I tried to outline possible characteristics of a person I wouldn’t want to hire. Like I said before, neither of the triggers mentioned in this or previous post can make me reject the candidate — they only give me a hint on what to look for and which skills and aspects of personality to analyze. It helps spend less time on interviews and also allows me to maintain a clearer understanding of the traits that I expect and don’t expect from the great developers, QA engineers and analysts we are looking for. I promise to return with a more positive attitude in the next post and review the behaviors that make candidates look good to me.

Intervieweing Developers: triggers, part I

The series:

Interviewing Developers

Interviewing Developers: triggers, part I

Interviewing Developers: triggers, part II

Interviewing Developers: triggers, part III

This post also appears on my blog in Medium.

Recently I explained the key principles that I follow when interviewing developers, but didn't cover an important aspect - the triggers that may significantly influence the flow of the interview. The trick is the more you do interviews, the better you deduce the character of a candidate from some of their behaviors. In particular, I certainly learned to notice particular responses that the candidates we don't hire may give. Even though one can't base the final decision on a single phrase, these triggers may both save some time and allow to avoid fatal mistakes. To begin with, here are 4 phrases that I heard from some developers.

Candidate: "Normally I work in IDE, so I can't solve this exercise on paper"

I've seen this one several times and it always came as a surprise. Yes, we love paper-programming! We ask quite some practice questions, but hardly ever give the candidate a laptop. I acknowledge that developers rely a lot on the comfort of IntelliSense, ReSharper and ability to run the code and tests that a laptop with an IDE provides. At the same time, offering to do an exercise on paper we want to check certain things about the candidate and refusal to undergo this check is what brings me closer to rejecting.

The idea behind coding without an IDE and compiler is that it allows us to see how a programmer makes assumptions about their task and tools and acts under a healthy portion of uncertainty. In other words, paper-programming focuses more on how you think and approach programming, than on your ability to brute-force the solution by trial and error. I interpret such a dependency on one's tools as unwillingness  to think and work under unfamiliar conditions, which for me means being unable to adapt to temporary difficulties and generally far from what we call a professional.

Candidate: "It doesn't matter that I can't solve the dumb programming exercise - I am good at real problems!"

Here it is dead simple: no, you aren't. Not unless you can show that and the "dumb" exercises are here exactly to allow you to do that. The purpose of sample problems is to verify certain skills. that we expect our potential employee to possess, and to see what kind of mistakes they make. If a person fails at this it doesn't mean we won't hire them - in many cases we spot what we need even behind a failure. But if someone tries to sell us the idea that, while they can't solve our mostly simple tasks, there are some mythic problems that they address easily, that is a sign of a phony, who speaks a lot, but does little. I don't think that loud yet empty bragging is characteristic of a great developer, be they junior or senior, - I believe they either succeed at a task or accept the failure and use the discussion to analyze their solution and spot mistakes there.

Candidate: "I don’t remember the theory - it's only practical considerations that are important"

It's not that our job is about reciting some "Introduction to OOP" book to each other, but it certainly hurts when people respond this way to a question like "what polymorphism stands for?". I expect some respect for the theory simply because it helps do our work better choosing the most suitable solutions and gives us a language to communicate with each other. Because the questions I ask are quite basic, those who fail to answer may have difficulties understanding software requirements and commit stupid mistakes. I'm pretty sure that someone who doesn't remember the key principles of OOP or can't explain the internals of a hash-table from the top of their mind can do good as a developer, but not when they denounce knowledge. Here, in addition to an attempt to gain my confidence by empty talk, I see reluctance to learn, which means I would have to invest a lot of time and effort into bringing the person up to the team's pace and establishing communication with them - the time and effort that I likely won't have.

Interviewer: "Could you please elaborate the answer and explain your reasoning?"

Candidate: "I just think that's the correct answer"

Interviewer: "What makes you think so?"

Candidate: "I just think so"

I was very surprised when I had this dialogue for the first time, but it was real and happened to me more than once since then. Sometimes I meet people who just come across a thing that looks like an answer to the question and try to sell it to me as though that's simply the answer that I need. As I must have repeated several times already, I am looking at the person's reasoning and striving to understand them better - not just trying to check whether they are able to guess a number. Even though it makes me feel somewhat stupid, it's not even the fact that this dialogue comes after I give some hints to indicate that the answer is incorrect that is most annoying. The problem is that such attitude shows that the candidate is bad at explaining their solutions and will hardly be able to contribute to a discussion of a complex problem with their ideas, not to speak of guiding other programmers and any kind of seniority. Even worse, like all the phrases above, this one is a sign of refusal to exercise one's brans - a very unlucky feature for a developer.

As you can see, these triggers show something about the person's approach to solving problems - not about which technologies they know or what tools they mastered. I pay that much attention to this aspect because it is relatively easy to teach a curious and thoughtful programmer a new language or a nice trick, but way more difficult and unrewarding to attempt raising a good developer from a person who doesn't want to study and sometimes even to think.

Even though hearing any of these phrases doesn't mean I would instantly stop the interview and refuse the candidate, they greatly impact the outcome of the interview. I have seen other managers hiring people who failed to solve an exercise or answer a couple questions and did that myself too. Still, I haven't yet met a person who behaved in the manner described above during their interview, but gave enough reasons to hire them nevertheless.

There are a couple other ways in which a candidate can draw my attention - both in positive and negative ways. I will get back to these in future posts. In the meantime, what do you think of these triggers? Do you believe they are valid or should interviewers be more forgiving?

Interviewing Developers

The series:

Interviewing Developers

Interviewing Developers: triggers, part I

Interviewing Developers: triggers, part II

Interviewing Developers: triggers, part III

Our company has been experiencing rapid growth during the recent years, which means we were hiring a lot. Managing one of our teams I took my part in the process and conducted a significant number of interviews. When I first faced the task of evaluating a candidate for the software engineer position a couple years ago it felt very awkward and difficult, but over time I developed a general approach that helps me go through the interviews easily and quite efficiently.

Of course the key point about the interview is which questions to ask. In the beginning my attempts to come up with relevant and challenging ones were very painful. I struggled a lot and jumped from one topic to the other always being sure that I miss something important. However, when we speak of technical knowledge and skills, it turns out that the most fruitful questions to ask are quite simple. For example, I usually focus on basic textbook-level Object-Oriented Programming and C# topics. Keeping things simple you may quickly see that the candidate demonstrates only shallow knowledge and, which is more important, inability to explain technical stuff in plain and simple words with reasonable examples. Such an outcome means an end to an interview - if a person can't discuss basics they likely won't be able to reason clearly about the complex stuff that your team deals with. On the other side, the potential employee may show great ability to articulate the subject and its practical implications in such a way that you see the experience behind their words and learn quickly that you're not wasting time with them. In this case you may proceed with more complex problems, but this is rarely necessary unless you're looking for some very specific skills. 

Simple practice exercise have the same advantages and provide enough insight into the way the candidate reasons and knows his tools. Even the easiest programming problems usually give enough room for mistakes and bugs and allow to get a good evaluation of a programmer's skills. It may be a good idea to challenge the candidate with some really serious coding puzzle, but you definitely don't want to start with that. Because the technical interview is to large extent about assessing candidate's abilities to analyze problems and explain solutions we also always offer a logic problem. Being an exercise suitable for the 5th grade or something like that, it still tells a lot about the way a person would analyze the situation and draw conclusions, not to speak of their explanation skills.

Still, you don't want you candidates to spend the whole interview fighting boolean algebra, so you will need some reasonable practice problems. One good place to look for these is the domain that your software models. It is usually enough to spend a couple minutes thinking of what you do on duty to come up with a couple great yet moderately difficult problems. Just keep in mind that these should not require too much context or be too large, so that you can stick them into the timeframe of the interview. For instance, my list of practice problems includes an SQL question that I faced when developing one of our features - it is a pretty real-life yet very simple and thought provoking problem.

While technical questions usually take the most of my interview time, I also dig into the personal experience and attitude. Our HR talks to every candidate before I get to them, but I still find it very important to discuss the potential employee's background and soft skills. Anyway, I have to check whether the person will fit into the team and will be able and willing to do a good job. In additional to usual questions on their duties on the last job I love to ask for a couple achievements, which they feel proud of - people are frequently taken aback and start to dig for their best, which makes the answer very valuable. In addition to unveiling the candidate's experience, such questions allow to assess personal traits. For instance, I can learn a lot about the person's involvement into their job - good candidate would usually be able and happy to speak about their duties and achievements, explain them in depth and do it in such a way that I will get interested even with little context. The way a candidate speaks of his tasks and situation in the office also tells a lot about their attitude and motivation and may uncover teamwork-related risks.

To ensure that both technical and non-technical questions are informative and easy to handle I have them written out carefully and usually ask the same ones, mostly in the same order. Even though this might not seem important, it plays a great role as it prevents hesitation and fears of forgetting something crucial. Additionally, if I follow more or less the same path through the interview, it becomes easier to utilize past experience to spot patterns in the way candidates respond and dive deeper into certain subjects. Finally, this helps to compare candidates to each other, which is quite hard otherwise.

Another aspect of conducting interview, that I find very important, is to be kind. When I am open, attentive and helpful I can definitely learn more about a person than if I demonstrate them my superiority or show that I want to get away as fast as possible. A candidate in an interview usually puts enough emotional pressure on themselves, so there is no need to introduce any artificial stress. This helps not only throughout the interview, but after it as well: I may decide to make an offer and in this case I'd better have the person willing to work with me - not being frightened to death.

Thanks to all these tiny how-to's I got much better at doing interviews, but I still face certain issues. In particular, sometimes I pay too much attention to the person's communication skills. While their ability to speak and listen means a lot and helps both integrate them into the team and teach whatever is important to our business, there are many valuable hires in the world of programming who might be a bit tough to talk to. I also tend to try too hard to find pros about the candidate - in particular when it is already obvious that I won't hire or recommend them. I constantly fight this trait, but it requires a degree of discipline to cut off all of my willingness to understand the person better and say a firm "no" quickly. One inevitable consequence is that my interviews take a lot of time, but at least I know how to shorten them.

Still, the most unpleasant problem about interviewing and hiring may come in the process of making a hiring decision. It can be really tough when I think good of the candidate, but at the same time have a feeling that something's wrong with them. In most cases such sensation means no offer - even though I can't explain what bothers me, the hesitation is a good indicator of hidden problems, which may surface later. In spite of knowing the general rule "doubt = no hire", I sometimes have a hard time making the "no" decision and need to work on that too.

Despite these issues, the simple practices outlined above, like having a regular question list and focusing on candidates' reasoning abilities allowed me to become more efficient and confident on the interviewing side. In particular, this helped to hire several great team-members who have already delivered great results and became valuable employees. Overall, interviewing is not too difficult a process, but it takes some time to get it right. I'm still actively working on improving in this area, so please share your insights and how-to's!