How should you interview for QA positions?

Question

Joel has his "The Guerrilla Guide to Interviewing (version 3.0)", but that's really for programmers.

How should you go about interviewing testers?

We ask programmers to program on a whiteboard; how you can you ask testers to test in an interview, in a way that tells you something useful about them?

Answer 1

You can ask people to test on a whiteboard too - draw up a sample dialog, or system, and ask them to discuss what ideas they'd have for testing. I really like Cem Kaner's approach to this. He goes into some detail about how he conducts test auditions - he tends to give two similar examples, with the first one as a practice run.

I've found it very revealing to see how different candidates react to being asked to come up with test ideas for a sample dialog. Some run out of ideas very quickly. Some people are very single-track minded, and all their test ideas are along the same lines. Some people ask hardly any questions, and others ask lots. Watching what kind of questions people come up with gives me an insight into what kind of mental model they're building, and what their blind spots are.

I've also tried giving people an actual app during an interview - I didn't find that much of an improvement on the whiteboard, personally, but it's possible that a better choice of app, or framing, would have helped there.

I'm not so much of a fan of "test this lightswitch" or "test this pen" questions - I prefer things that are close enough to real that they trigger genuine questions for people. I know some people have difficulty in getting inspired by things that don't seem like authentic problems, and I don't want to disadvantage potentially promising candidates.

Answer 2

We have several portions to our interviews:

• Here's a simple, well-known system anyone should know, we like to use elevators. Here is a very basic spec. Talk about some tests you'd run.
• We've written the spec so that anyone worth their salt should have a dozen questions about it.
• We want to see the different types of tests they come up with, not just the specific issues.
• See how curious they are about things. Good testers test everything all the time, including you and your interview process.

I like to say (metaphorically) that when you ask a good tester to pick a number between 1 and 10 they'll choose π.

Answer 3

I think it depends on what you want your testers do to. If working in a team environment and collaboration are key aspects of what your test team does, make them solve a testing problem with you. If you want them to write some automation or tools (or at least be able to if they're stuck), you may want to have them write some code (but have them write code to solve a testing problem - not some "interesting" algorithm).

In general though, I like to take some time before the interview to think, "What would the A+ tester on this team do?". I create a list of attributes, then brainstorm questions that will help me figure out if the candidate has those attributes.

And finally, where I work, career growth has a huge emphasis, so I probe a bit to make sure the tester I'm hiring has long-term potential (I like to ask, "How do you learn?", as this gives me an indication of how much they want to grow).

Answer 4

In addition to giving them an app to test, I've had good luck with showing testers a set of requirements and then letting them ask questions about the requirements and start to brainstorm tests from them. I try to make sure the list of requirements has some vague statements in them to see what kind of questions people will ask.

Answer 5

I agree with testerab that Cem Kaner, in his PDF, has outlined a good approach to hiring.

Paul Carvalho also has a good PDF called Hiring Software Testers in an Information Age that he published in 2007. Besides conducting the interview, you as the interviewer should look for common attributes, be able to skim through resumes, identify the school of testing they belong to, identify revelant work experience, etc.

I found Paul's PDF after reading his article Hobbies and Interests. The article has a lot of good information on hiring testers which Interviewees can look at to get an idea of what someone might look for. In the comments he lists a few examples of the types of problems / sample applications he gives to testers. Its worth a read.

Cem Kaner posted in Dr. Dobbs on Recruiting Software Testers back in 2000 that's worth a view as well.

I used to think quizzing testers on their vocabulary (i.e. what does verify mean?) was a good idea but I learned quickly it didn't matter. We all have different ideas on what things mean and the value they carry - as long as you can articulate your reasoning.

Answer 6

From my experience i feel what ever questions need to be asked should be practical ones rather than theoritical. I have come across few of my friends who have just mugged up on theoritical knowledge and have cleared interviews, in reality they have no practical knowledge(I am talking wrt to lateral hires). Based on project requirement and the knowledge required that a tester should have,a set of questions has to be prepared along with few basic standard questions. It is best to avoid questions on asking different types of testing i.e what is black box testing,white box testing,exploratory testing and so on.. People get in answering such questions.

Answer 7

I think that this is well covered by Steve McConnell in his book "After the Gold Rush", where he states that you should make jugglers juggle before you hire them, so make them test in the interview.

For example, pick a piece of commonly used software, like say copying a file to a folder in windows and ask them "You are the test lead on this, what would you want to test before you ship it." Good testers will be able to tell you hundreds of test cases, poor testers will struggle at 10-20 obvious ones.

Answer 8

I try to understand whether they actually like testing or whether they're using testing as a stepping stone into development. What you do with that information depends on the organization, although if they don't actually want to test, you may have problems with the quality of their work.

Answer 9

I can give an example of how not to take testers !

In the Indian IT industry, some of the companies recruit or assign Fresh Under grads to testing team, by 1) Names starting A <--> M - Development Team, N <--> S - Testing Team & rest will be in PMO etc & if the candidate did not cleared the Programming language test(cut off limit for developer positions) but still scored a decent mark, then will be assigned to test Team. There are many permutation & Combinations like the above.

Main problem for these companies is they have to recruit in thousands every year.

Answer 10

Take something you know well and just see how your interviewee would approach testing it from the highest level and describe their thought process before they begin.

You probably want to know more how they think rather than whether they do it the "right" way.

Answer 11

1. The common sense of a tester. Check if s/he is sensitive to the product testing.
2. The knowledge of test methodologies.
3. Experience.
4. Talk about the chanllenges that s/he met in the past
5. Take a real system for example, or a pen, a cup, a selling vendor machine to ask s/he to think about the test cases.