How to phone-screen programmers and not go insane

Technical phone screens are hard to do right. Yet, they serve an important role. They are the primary filter that ensures you only bring in appropriate candidates to spend valuable hours meeting your team. If you don’t phone-screen correctly, you’ll end up bringing in some real timewasters who don’t even come close to having the technical chops or the personality to make it through your in-person interviews.

Your hiring process is a classic funnel and the phone screen phase is near the top of it. That means that a ton of resumes will land on your desk (along with a boatload of eager emails and voicemails from your recruiters), and at each stage you will cast aside a very large percentage of them.

We just finished hiring for four engineering positions here at TimeTrade. Here are the metrics we saw at each level of the funnel:

  • 120 resume reviews
  • 53 one-hour technical phone screens
  • 22 four-hour first-round interviews
  • 9 four-hour second-round interviews
  • 4 actual hires

As any sales or marketing person will tell you, the more you put into the top of a funnel, the more results you’ll get out at the bottom. That’s just as true of recruiting, too. Your challenge therefore is to figure out how to do lots of phone screens without compromising their quality or your sanity. Here’s how.

Schedule Efficiently

The seemingly simple act of setting up the phone screen is usually where you will find your free time disappearing, and fast. As a hiring manager, you almost certainly have a calendar full of existing meetings and commitments, and trying to get dozens of extra appointments with candidates requires a lot of calling, emailing, chasing and waiting. Sometimes the recruiters or candidates will get things wrong and end up double-booking you, causing even more hassles for you to reschedule around the conflicts.

But that’s not everyone’s experience. In fact, it takes me all of 30 seconds to set up an entire two weeks’ worth of phone screens.

It’s not magic that allows me to do that – it’s technology. Instead of me doing all the negotiation and scheduling, I simply use TimeTrade’s online appointment scheduling tool to share my open times for phone screens (for example, 2-4pm every weekday) and it gives me back a single URL that I can email in bulk to all my potential candidates and recruiters. That email might look something like this:

I’d like to phone screen you for the engineering position here at TimeTrade. Please click here to choose one of the available times to speak with me.

– Brian

The product is integrated with my Outlook calendar, so the moment a candidate chooses a slot it drops onto my calendar without any effort on my part (and they can add it to their own calendar too, of course).  I’ll admit I am biased since I work for the company, but I can’t imagine going back to spending hours scheduling appointments the old, manual way I did before.

Be Prepared

Now that you’ve scheduled your phone screens, you need to run them efficiently and learn as much as you can about the applicant’s skills and personality. Unless you’re extremely experienced in this area, you won’t be able to “wing it,” at least not without sounding like you aren’t very prepared. Having a list of potential questions and areas to probe is an absolutely necessity, and it will give you more confidence to run the phone screen properly if you’re new to doing them.

Importantly, you should make sure to have a number of alternative questions available for each area you would like to probe, and use different ones each time. It’s quite common for friends or colleagues to apply for the same position, and they might share their questions to give their buddy a better chance of being brought in for an interview. If nothing else, it can bring a bit of variety to the process that keeps you interested in it when you’ve just completed your 30th phone screen in 4 weeks.

Code Online

The most important thing to test with a software engineering candidate is their ability to solve problems by writing code. After all, that’s what they’d be doing if they got hired.

Sadly, most phone screeners never tackle this area because they believe they’re limited to questions that can be asked on the phone. That means lots of questions about the details of software (such as, “What class library would you use for socket I/O?”) but almost none that would help you gauge their problem-solving and programming abilities. Of the few people out there who do make people code over the phone, some of their proposed methods (like having the candidate write their code on paper and dictate it back to you) are pretty clunky.

Enter the free and simple online collaboration tool TypeWith.Me. Problem solved.

Right before the phone screen starts, I email the candidate a URL to a new “document” hosted on that site. When they click on it, they’ll see an empty document in their browser, but anything they type in it will be immediately visible to me. In addition, anything I type will show up on their side too. Think “Google Docs without any registration required”, and you’ve got the idea.

I’m able to paste in a few lines of text from my script that outlines each problem I’d like them to solve (reverse a linked list, compute the Nth Fibonacci number, etc.) and sit back and watch them code in real-time. Since they’re also on the phone, we can easily discuss their overall approach or I can interrupt them to tell them to reconsider that if (a = 0) statement they just typed in.

To make sure this whole process works, you need to inform your candidates ahead of time that they’ll be asked to use this kind of tool because they’ll need access to a speakerphone and the Internet. All of these instructions are visible when you click on my TimeTrade URL so each candidate gets to read them before picking their appointment time.

You’d be amazed at how many candidates refuse to even start writing code, indignantly claiming that their years of industrial experience mean that they shouldn’t have to perform these types of tests. By claiming as much they will have self-selected themselves out of the process, and I’m always happy to inform them of that fact.

Sell Something

Always take the time during the call to sell the company, the team culture and your products. Do this even if the candidate is terrible and would never, ever get hired for your team. A phone screen is as much of a marketing and networking opportunity as it is a chance to make the right hire. You never know when your paths will cross again, or what friends your candidate might refer to you.

Running a screen efficiently using the tools and techniques described earlier shows that you and your company are professional about hiring and take your phone screens seriously. Don’t underestimate what this kind of first impression means to a candidate.

Track Your Progress

Now that you know how to schedule and run phone screens properly, the last thing you need to do is figure out how to track the workflow for each candidate as they make their way through the funnel.

I’ve used a variety of tools for this (Excel, Outlook and good ol’ paper) but they all were all lacking in some way. Recently I stumbled upon Trello and discovered that it is a complete – and free – solution for my hiring tracking needs.

Trello finally gives my team and I the ability to track where each candidate is in the hiring process and to move them effortlessly through the funnel. We can also store their resume there and avoid having to email it around all the time, and since it’s an online SaaS tool there’s no chance of some team members seeing stale information.

Technical phone screens are hard to do right, but the tips above should take them from being a sanity-draining chore to become a regular, enjoyable and effective part of your hiring process. You’re welcome.

2 thoughts on “How to phone-screen programmers and not go insane

  1. Hey Brian, these are fantastic tips. We have almost the same process, but we save code writing for the first round. I try to keep the phone screen to under 45 minutes with three objectives: Sell the company/role, see if they had exposure to concepts used in the code stack, and get some confidence that they can write some code when they come on-site. My biggest impediment is my self enforced time restriction.

    1. Some companies use two phone screens method — first phone screen hosted by hiring manager to sell, introduce and ask technical/behavioral questions. Second phone screen conducted by senior engineer to do coding test on coderpad. Each phone screen last for 45 minutes.

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