Let me start out by saying I want to damn the writers of the Toughest Developer Puzzle Ever – 2. It is eating every last shred of my free time! But as I've been churning through each puzzle and marvelling at the brain teasers and trivia within, I began to think about interviewing developers and why it seems to be so hard to find good ones. The problem is, it seems like no matter how hard we try to find the perfect way to separate the chaff from the wheat, inevitably someone will get hired who falls far short of expectations or someone will get passed over for missing a piece of trivia or a tricky brain teaser that could have been an excellent team member.
In shops that are primarily software-producing businesses or other heavily IT-oriented businesses (Microsoft, Amazon, etc) there often exists a much tighter bond between HR and the hiring development staff because development is their life-blood. Unfortunately, many of us work in places where IT is viewed as a cost or just a means to an end. In these shops, too often, HR and development staff may work against each other due to differences in opinion as to what a good developer is or what one is worth. It seems that if you ask two different people what makes a good developer, often you will get three different opinions.
With the exception of those shops that are purely development-centric (you guys have it much easier!), most other shops have management who have very little knowledge about the development process. Their view can often be that development is simply a skill that one learns and then once aquired, that developer can produce widgets as good as the next like workers on an assembly-line floor. On the other side, you have many developers that feel that software development is an art unto itself and that the ability to create the most pure design or know the most obscure of keywords or write the shortest-possible obfuscated piece of code is a good coder. So is it a skill? An Art? Or something entirely in between?
Saying that software is merely a skill and one just needs to learn the syntax and tools would be akin to saying anyone who knows English and can use Word can write a 300 page book that is accurate, meaningful, and stays true to the point. This just isn't so. It takes more than mere skill to take words and form a sentence, join those sentences into paragraphs, and those paragraphs into a document. I've interviewed candidates who could answer obscure syntax and keyword questions and once they were hired could not code effectively at all. So development must be more than a skill.
But on the other end, we have art. Is development an art? Is our end result to produce art? I can marvel at a piece of code -- see it as concise and beautiful -- and yet that code most perform some stated function with accuracy and efficiency and maintainability. None of these three things have anything to do with art, per se. Art is beauty for its own sake and is a wonderful thing. But if you apply that same though to development it just doesn't hold. I've had developers tell me that all that matters is the end result and how you code it is entirely part of the art and I couldn't disagree more. Yes, the end result, the accuracy, is the prime criteria to be met. But if code is not maintainable and efficient, it would be just as useless as a beautiful car that breaks down once a week or that gets 2 miles to the gallon. Yes, it may work in that it moves you from point A to point B and is pretty as hell, but if it can't be maintained or is not efficient, it's not a good solution. So development must be something less than art.
In the end, I think I feel like development is a matter of craftsmanship. We use our tools and we use our skills and set about to construct something that satisfies a purpose and yet is also elegant and efficient. There is skill involved, and there is an art, but really it boils down to being able to craft code. Crafting code is far more than writing code. Anyone can write code if they know the syntax, but so few people can actually craft code that solves a purpose and craft it well. So this is what I want to find, I want to find code craftsman! But how?
I used to ask coding-trivia questions a long time ago and many people still fall back on this. The thought is that if you ask the candidate some piece of coding trivia and they know the answer it must follow that they can craft good code. For example:
What C++ keyword can be applied to a class/struct field to allow it to be changed even from a const-instance of that class/struct? (answer: mutable)
So what do we prove if a candidate can answer this? Only that they know what mutable means. One would hope that this would infer that they'd know how to use it, and more importantly when and if it should ever be used! But it rarely does! The problem with triva questions is that you will either:
Approve a really good developer who knows what some obscure keyword is (good)
Reject a really good developer who never needed to use that keyword or is too inexperienced to know how to use it (bad)
Approve a really bad developer who googled "C++ Interview Questions" and studied like hell but can't craft (very bad)
Many HR departments love these kind of tests because they are short and easy to defend if a legal issue arrises on hiring decisions. After all it's easy to say a person wasn't hired because they scored 30 out of 100 on some trivia test. But unfortunately, you've eliminated a large part of your potential developer pool and possibly hired a few duds. There are times I've hired candidates who knew every trivia question I could throw out them and couldn't craft. And then there are times I've interviewed candidates who failed all my trivia but who I took a chance on who were my best finds ever.
So if not trivia, then what? Brain teasers? The thought is, these type of questions measure the thinking power of a candidate. The problem is, once again, you will either:
Approve a good candidate who has never heard the problem and can solve it (good)
Reject a good candidate who just happens not to see the "catch" because they're nervous or it may be really obscure (bad)
Approve a candidate who has studied enough interview brain teasers (once again, you can google em) to recognize the "catch" or knows the answer already (bad).
Once again, you're eliminating good candidates and possibly accepting bad candidates. In these cases, I think testing someone with brain teasers only tests their ability to answer brain teasers, not the ability to craft code.
So how do we measure someone's ability to craft code? Here's a novel idea: have them code! Give them a computer and a compiler, or a whiteboard and a pen, or paper and pencil and have them construct a piece of code. It just makes sense that if we're going to hire someone to code we should actually watch them code. When they're done, we can judge them on several criteria:
Correctness - does the candidate's solution accurately solve the problem proposed?
Accuracy - is the candidate's solution reasonably syntactically correct?
Efficiency - did the candidate write or use the more efficient data structures or algorithms for the job?
Maintainability - was the candidate's code free of obfuscation and clever tricks that diminish readability?
Persona - are they eager and willing or aloof and egotistical? Will they work well within your team?
It may sound simple, or it may sound crazy, but when I'm looking to hire a developer, I want to see them actually develop well-crafted code.
