This question is a great positive indicator, but a terrible negative indicator.
That is to say, a person who works on a lot of stuff in their spare time is very likely to be someone I'd like to hire. The reverse isn't true, which is why there are other questions in the deck. I realize that there are great developers who don't have a well populated github profile and dozens of side projects.
If I had a candidate that had trouble with the question, I'd expect them to say so. I'm a pretty reasonable person. I would not expect them to try and exit the interview early with little to no indication why.
If you're interviewing an parallel universe's patio11-equivalent, and they say, "I have been running FlashCardCreator.com since 2001...", and goes on to explain neat things about what she's learned from it, it sounds like that should be a big green flag. Not only is such a person likely to have lots of cross-domain insight, but they clearly have the mojo to deliver working code.
If you're worried that they might decide that their work-outside-yours is going to cannibalize their time, they probably have an answer for why you don't need to worry much about that. (After all, they __did__ apply.) I would be surprised if you had to worry about them leaving any more than you would any other developer.
I want to see if your eyes light up when you talk about it.
I couldn't imagine working that often and not enjoying it.
> Ask me that question and I'll probably
> find a way to wind up politely and leave.
For me, as a potential employer, that would be a good reason not to want to hire you. It makes you sound like you would not be an easy person to work with. It sounds like if someone came to you with an unreasonable software requirement you would simply shut them down without trying to find a way to deliver something that finds a good balance between what they've asked for, and what can be done.
But perhaps that's not the impression you intended. If not, could you expand further?
However, as an employee, such questions might be highly correlated with past companies that are looking for people who do not have family commitments, or who are willing to do unpaid extra work at home "for fun". As an interviewee, it makes me wonder, even if only fleetingly, "Will I be discriminated against for not being (young+single)?". (Are we even allowed to ask about marital status or age?)
Even if such a thing was never your intention, the interviewee might have had prior bad experiences with those who ask such a question, and view cutting the interview short as a way to ensure they don't get mistreated later.
But I understand the point point of view, I'm just trying to give some balance, and point out that the black/white attitude this suggests is sometimes a clear indication that you are not cut out for a particular position.
Regardless, if it makes me not want to work for you, and you don't want to hire me because of my reaction to the question, then my likely response would be win/win, right? :)
Then again, maybe you would not be a good fit. My comment is simply that based on just one question you are actively avoiding finding out.
I'm always confused when I see this sentiment. I only ever see it on HN, and only when someone feels they've been asked a question below their station or that is inherently insulting.
I've never used this as an only question, but I have got better results from people who have used their skills to solve some problem for themselves, but that isn't unique to programming.
Heuristics are, unfortunately, quite valuable in hiring scenarios, especially for start-ups.
It's also just much more fun to work with people who love programming, and an easy way to tell (even if it's susceptible to a few false negatives like your friend) is to find out if they program in their own time.
The only exception to this was a guy who did amazing work on side projects, but the work he did for his paying job suffered significantly...
The thing is though, you can love programming and find that 40 hours a week of it is more than enough. I think what you'd find with this heuristic is that it tends to favor young people. It's a lot easier to be enthusiastic about some side project when you're 20 than when you're 40 and have a lot of responsibilities.
So I'm not sure why the person without personal projects needs to demonstrate that they're keeping tabs on the industry any more than someone who does.
Seems like you want to ensure X by testing for Y and mistaking correlation with causation.
I disagree. If passion is an important quality to you, then, as the interviewer, you need to ask questions that reveal whether or not the candidate has that quality. It's absurd to ask about personal projects as a proxy for asking "are you passionate about programming" and then to expect the candidate to guess your true intentions and answer accordingly.
First, I have a family now, and spending time with them is more important to me than any job. (And any company that has a problem with this is not a good fit.)
Second, I've been lucky enough to find jobs that are interesting and intellectually stimulating. My first programming jobs were kinda boring, so I had extra creative energy and learning and building things was an outlet.
Third, owning a home always involves upkeep and fixit projects. These can be fun and are generally easier get my kids to involved in than teaching them to program (going back to #1).
I'm in the office 40-45 hours a week typically, I spend 20-30% of my time just thinking about the problems I am solving, or stuff like this, or following github projects, or other technology reading. I probably do about 4-5 hours of actual programming a day at work. My output during that time tends to match or exceed most of my peers in both quality and quantity.
The problem is getting people to understand more hours isn't the same as more productive output. Spending a couple hours thinking through a problem (or even prototyping) will usually save you more time down the road. This is true from simple data modeling to working through how to fit a system together.
As to the original question.. it is far from the only indicator of a person's own skill and drive, but it is an indicator. Especially in more junior level candidates. There's also the fact that the technology in use changes rapidly... and do you take the time to learn it... either out of your in-office day, or outside.
It is not uncommon for people to feel this about a number of professions such as chefs, bakers, graphic artists, etc.
However, in my experience I prefer to judge an applicant on professional credentials rather than their free time because while it may tell me quite a bit about them it tells me little about their capabilities that I couldn't find out in better ways.