How do you judge the ability of the candidates during the interview?

Sometimes I find it hard to score their ability. I have seen some candidates with x years on paper yet does not know git more than push and pull.

Also there are few who didnt do very well at the interview, however we hired and doing quite well at work.

(As I also had a hard time getting a job before, I sometimes feel bad to reject some who seems to have good personality but didnt do well at work)

We give them ~4 hours take-home exercise, but with 7 days deadline, submit via github.

A person who really interested in the job will utilise all that time, we can tell by looking at their checkin history and the amount of effort they put in.

Also we can look at their code quality.

Poor performing candidates usually will do it as quick as possible, we eliminate them early.

At the interview day, we ask them to present their solution. We ask in-depth questions, throw in extra requirements, and see how they handle that.

This can never go wrong. I think asking coding questions on the spot will freak out people instead of getting the best out of them.

You're doing fine. You find it hard to score their ability because it *is* hard to score their ability.

All hiring processes are broken in one way or another. E.g. exercises like @nam17887 suggested are, not only because they highlight a too narrow part of an applicant's knowledge, but also because it puts those with family or any sort of obligation at a disadvantage.

I don't know the perfect solution either. In an interview I'd emphasize on the character of the person. Willing to learn? Free of ego problems? Then use the probation period to see how the person actually copes. Sort of "hire and fire", but with the clear intent to not fire.

Question previous experience, hand them a small exercise that can be complete in under a day but over a few days, and most importantly their social fit with the current team, hell do a meet and greet kind of thing somewhere if it's a small team - something informal.

There's no solid way to make sure the candidate is a perfect fit, but if they meet most of the criteria and the missing items can be learnt on the job, then go with that one.

A decent dev will always learn a new tool if the job depends on it.

@VaderNT My wife, who not only work 50 -60 hours a week but also take care of the kids, still spending her weekends on study to grow her career.

I wonder what excuse everyone else have for a take-home exercise?

@nam17887 with asking for "excuses", to me that sounds prejudiced/not open to other viewpoints. I'll nevertheless assume I just read too much into words.

So, like @halfflat and I pointed out, all processes are biased in one way or another. Which leads to self-selecting work cultures (or "hire-people-like-me problem").

E.g. take-home exams favor people with a lot of free time at home. (I know, duh.) Does that mean your wife stands no chance? Of course not. Though I'd be wary of sweatshops that select for exactly that: People with little free time that still let themselves be pushed to 110% by the company.

Now, would I do take-home exams again? Depends. Personally, I value my private life the most. I'm not giving it away for free, but a potential employer might be attractive enough. And after all, at least an interview has to happen on my free time, doesn't it.