How to make a good programming interview?

Question

I am doing interviews with from time to time to recruit some not bad people. And I really think I AM NOT doing to correct Job. I work in a company when We have to do a lot o DB programming, .NET programming, Java programming, so we need people who are open minded and not focused on a particular tech. Afterall language is a notation, You have to understand what is going under the hood.

I ask people about their project, ask them some coding questions (believe me a SQL question involving a CROSS JOIN is hard), let them write some code, ask them about oo design, ask them how they update their knowledge, and stay up to date, do they have FUN when they code (at least sometimes).

Hell I even give them a coding solution for home (3 hours max) to see how they think and code.

And yet my hit rate at hiring junior member (those who live over the initial 3 months) is just about 33%.

So my question, how do YOU make the good interviews, because I think my hit rate is to low? Do you have any best-practices(should be at least 60-70%)?

p.s. And i noticed that: the best programmers are lazy, but motivated, just being lazy is not enough:) But people who write the best code are attentive to details:)

Answer 1

http://i.seemikecode.com/

This Jeff Atwood guy tells about it in his website here: http://www.codinghorror.com/blog/2010/02/the-nonprogramming-programmer.html . You may wanna take a look.

Answer 2

How are you defining your "hit rate" of 33%? Are 2/3 of your initial hires a disappointment performance-wise, and getting fired? Or are 2/3 of them quitting after the first 3 months? If your hires are quitting, then your problem probably isn't with your interview techniques, it's probably with the position/job. Perhaps it's not as interesting as you make it out to be during the interview. Maybe you're not providing enough support initially to get your new hires up-to-speed.

Here's an interesting article on how Google's poorest-scoring interviewees tend to do the best at the company: http://www.businessinsider.com/googles-broken-hiring-process-2009-10

"One of the interesting things we've found, when trying to predict how well somebody we've hired is going to perform when we evaluate them a year or two later, is one of the best indicators of success within the company was getting the worst possible score on one of your interviews. We rank people from one to four, and if you got a one on one of your interviews, that was a really good indicator of success."

Perhaps you should focus more on the personality of your hire, rather than completely on interview skills? Ask yourself: is the human being sitting across from me not only qualified enough for the position, but also a good-fit personality-wise?

Answer 3

I don't think there is anything wrong with what you are doing, but I think there are some things you are not doing.

Do the candidates pass the "sits next to" test? In other words would you be happy if this is the person that sits next to you? You don't have to be soul mates, but you have to get along (in fact it's probably best if you aren't soul mates!).

Did you describe the job to them and figure out if the job will make them happy?

Are you sure you are interviewing for the job they will actually do? Sometimes the interview pattern stays the same but the job changes. You still say things about finding challenges and having great opportunities for learning new technology but the fact is you're stuck making websites dedicated to peoples cats.

Skills checks like you are doing are necessary, but they aren't sufficient. In the end programming is a people problem.

Answer 4

Have you tried any profiling? Reading the comment to Mike Cialowicz's answer, I wonder if you have a situation where the not-so-great hires were making a transition to consulting and didn't really get how different consulting would be from their previous experience. You mention lots of programming related checks, but none that are the "why do you want to work here?", or if the person is doing a big job change - like a product-centric position to consulting - "why the job change?"

IMO, candidates changing major focuses should be able to jump through a few more hoops. Understanding the business and the culture of the company hiring you is part of being a successful engineer.