Drowning in a C of Interviews
The Guerrilla Guide. It is the be-all, end-all of how to look for candidates.
Except for one paragraph.
And I’ve come to realize that I agree with that paragraph; just not Fog Creek’s implementation of it.
In The Paragraph In Question, Joel writes:
I’ve come to realize that understanding pointers in C is not a skill, it’s an aptitude.
The paragraph goes on. But for Fog Creek, it stops right there. In fact, it stops even earlier. The version that Fog Creek has implemented, in practice, reads:
I’ve come to realize that understanding C is not a skill, it’s an aptitude.
And you know what?
Well, that’s not true. Candidates were a lot more relaxed, and asked a lot fewer nervous questions about how strict I was going to be about syntax. But my confidence that I could tell whether they would be good programmers, and more importantly, my acceptance rate, didn’t change whatsoever. I certainly didn’t feel like I was losing any data by not conducting my interview in C.
How is that possible? Let’s read through what Joel actually wrote after that introductory sentence:
If you read the whole thing, you realize that Joel’s not advocating the idea that a candidate must know C; rather, he’s advocating the idea that C forces you to understand concepts that you may not otherwise understand.
Inventing questions that force candidates to understand pointers without using C isn’t too hard. Nearly any question that forces candidates to invent a data structure (e.g., a hashtable, an AVL tree, or the like) will test how they handle indirection, the idea that having a thing is different from having a pointer to that thing. So I’ve picked a question that forces candidates to design a data structure. And, sure enough, I see candidates who have a lot of programming experience, but who don’t “get it”, completely bomb out in my interview.
I think there’s a tremendous amount of value in Joel’s original point. Understanding indirection, and pointers in particular, seems to be innate. But doing interviews in C doesn’t really test for that; it tests for the candidates’ understanding of C. And I think, in our dogged pursuit of that, we’ve probably erred. We’re making candidates nervous about how well they know C, and focusing too much on how well they understand C’s semantics, but not really getting any meaningful indicators back in return.
For the moment, I’ll continue conducting my interviews in the language of the candidate’s choice as an experiment, but I think it’s inevitable that the Wall of C will fall.
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