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Phone Screen Advice from Expert Programmers

child-using-cell-phoneGetting the phone screen wrong is a pricey mistake. After pre-qualification with a programming challenge, technical skills have been initially vetted but it’s important to get the phone interview right to complete a winning combination. Here’s a roundup of advice from expert programmers to ensure phone screens with programmers are efficient and effective:
Can They Code? Programming Questions 2.0
Steve Yegge (Google) on stage at OSCON data.
Candidates coding in real-time while on the phone is a necessary part of any phone screen, (it’s one of Steve Yegge’s five essential elements in his old but still valuable post on the topic). Yegge describes the process used years ago to get this done:
“Give them a few minutes to write and hand-simulate the code. Tell them they need to make it syntactically correct and complete. Make them read the code to you over the phone. Copy down what they read back. Put it into your writeup.”
However, tech solutions have arrived to support the technical phone screen after Yegge wrote article, including Interviewstreet’s CodePair, a tool we built to seamlessly facilitate coding during phone interviews. With CodePair, you have all of the features of a dev environment to make the experience as realistic as possible, so you can spend more time on discussion and none on the candidate reading their code over the phone. CodePair also has a handy playback feature so a reviewer can take a look at how a candidate built their code after the phone interview has ended, for example.
Critiquing and Debugging Skills
As Pete McBreen suggests (author of Software Craftsmanship and Questioning Extreme Programming), asking a candidate to review a sample of your company’s code serves a dual purpose: managing the expectations of the candidate, and determining their level of expertise. Junior programmers can often do well on a programming challenge but have no idea how to track down an error. This is satisfactory if you’re hiring for a junior position, but debugging knowledge is a good way of engaging with as advanced candidate.
Jeff Atwood - InterviewstreetImpossible Questions:
If you already ask “impossible questions” or are considering incorporating them into your phone screens, Jeff Atwood in says it best:
“Ask an impossible question that has some relevance to a problem your very real customers might encounter. I just can’t muster any enthusiasm for completely random arbitrary problems in the face of so many actual problems.”
Just like debugging questions can be used to introduce candidates to what they’ll be working with, impossible questions can function as a brain teaser, an estimation opportunity, and a peek at what the candidate will tackle in the role.
Cultural Fit Questions
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The easy route is to rely on stock queries to determine cultural fit. Replace “Describe the work environment or culture in which you are most productive and happy” or “What is your preferred work style?” with targeted questions based on likely scenarios: “When you have a day off, is it acceptable for a colleague to call with a brief question about some code you’ve written recently?”
Round out the cultural fit segment of the interview with open-ended questions that can score information on a candidate’s personal interests, priorities, and appetite for learning/discovery: “Which sites do you visit every day? Which books would you recommend as a must-read?” or even “What’s your favorite recent article on Hacker News?”
Other suggested areas to cover in the phone interview include:

  • Asking a candidate for a high-level design of a small system
  • Reviewing a candidate’s portfolio of published code
  • Querying with basic object-oriented programming questions, regular expressions or other categories relevant to the position

An overarching theme to select some good technical questions suited for the position you are filling and challenge people to answer them, without the answer being dependent upon “tricks” or a single bit of specific knowledge. Present your general areas of enquiry without expecting every candidate to answer perfectly… isn’t a phone screen is a rough gauge to build on the programming challenge and determine their suitability for an on-site interview? If you take this approach, and apply it consistently across a large number of candidates, you’ll begin to see trends emerging that will help you optimize your phone screen and ultimately make a better hiring decision.
Lead image via DigitalTrends



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