As at many tech giants, interviewing for a technical position at Microsoft used to mean answering surprise brain-teasers. For example: "How many ping pong balls would fit in a 747?"

Not anymore. Over the last couple of years, the developer group at the company has completely revamped its interview process, according to John Montgomery, partner director of program management. He explains his reasoning in a blog post on Medium that's well worth reading for anyone who ever has to interview job candidates. 

The revamp was inspired by what Montgomery calls "a series of small epiphanies." Among them: That not everyone performs best under pressure or with surprise challenges, and that the best way to learn what it would be like to work with someone on solving real problems work with that person on solving real problems.

Here are some of the most significant changes Montgomery and his team made as a result:

1. No more surprises.

Candidates for developer jobs no longer have to scour Glassdoor to try to suss out what questions or challenges they can expect during a Microsoft interview. Now, Montgomery writes, "We let the candidate know a few days in advance what the interview day will look like and what problem we'll be working on. We give them time to do their own research and to think about it." After all, he says, most of the time employees know in advance what they'll be doing at work every day. Why should an interview be any different?

2. Candidates work with employees on solving actual problems.

When Montgomery started at Microsoft, interviewers were still asking why manhole covers are round, and how many ping pong balls fit in a 747. In 20 years, he says, he's never had to write the code to fill a 747 with any kind of ball. 

So why ask about stuff that's imaginary when the team is already working on problems that are real? Instead, he writes, "We run through a real problem the team is trying to solve--improving satisfaction, increasing retention, boosting usage of a service or feature." Not only that, the candidate is given all the relevant data that the team is working from, and is welcome to use the internet to find more information to help solve the problem. Working together on a real problem with no secrets helps interviewer and interviewee have a collaborative conversation.

This means changing the usual logistics of a job interview, he adds. Traditionally, a candidate would proceed from one office to another, meeting with different interviewers. But because the candidate is usually be working on a white board, writing things that will be needed later, he or she now stays in one conference room during the interview process, and interviewers come to the candidate.

3. Interviewers work in pairs.

This was the most difficult change to make because it made interviews both more expensive (in terms of executive time) and harder to schedule. It was intended as a way to train less experienced interviewers. But the team soon saw that it made for better interviews, too. "Not only was the conversation more dynamic with multiple collaborators, it also gave us an opportunity to hear multiple perspectives on the same conversation," Montgomery writes. "Not everyone hears conversations the same way, so it gave us a way to place a check on unconscious bias in the same conversation."

Job candidates love it.

After a couple of years of doing this, Montgomery and his team are pleased with the results. Early on, they worried that job candidates faced with two interviewers instead of one, and a real business problem to help solve over the course of the day would feel particularly nervous. Instead, nearly every candidate told the team that they had never encountered a process like this before but it really helped them understand the business and the team. 

In fact, one candidate who got competing offers from "other large Seattle tech companies," chose Microsoft because she liked the process so much, Montgomery reports. She was one of the first candidates to be interviewed by this new method and she's still there doing very well, he adds. "Ultimately, the goal of a hiring process is to bring great people into the team or company--to make sure they're a fit and will succeed, and to create a great experience for them so they want to join," he writes. This new interview method does just that. It's something every company could benefit from.