By 2013, Google was adding nearly 5,000 people to their organization every year. To keep up with the pace, they could no longer rely on referrals as their only source of smart creatives. Their internal networks seemed to have been completely tapped out.

So, like others, Google began leveraging job boards. This was great at getting applicants, but now they were having to sort through over 400 resumes before they found a single superstar worthy of an offer. In perspective, this meant that it was twenty-five times more likely to get accepted into Harvard than it was to get hired by Google.

Part of the reason for the astonishingly low hire rate was due to the limitations of the portals themselves. Top performers, by virtue of them excelling in their positions, were very unlikely to actively pursue new opportunities on their own (at least at this point in Google’s history). Because of this, most of the candidates that applied via job boards were completely unqualified.

Still, much of Google’s extreme selectivity was intentional. They were simply unwilling to compromise on quality just to fill jobs. Laszlo Bock, former SVP of People Operations, explains: “Our hiring machine was overly conservative by design. It focused on avoiding false positives – the people who looked good in the interview process but actually would not perform well – because we would rather have missed hiring two great performers if it meant we would also avoid hiring a lousy one. A small company can’t afford to hire someone who turns out to be awful.”

The drawback with this approach, however, was that it slowed the hiring process down to a near halt. In fact, many of the best candidates would remove themselves from the recruitment cycle because it took too long, was too onerous, or they didn’t feel adequately pursued.

Facing these challenges, Google was forced to get more creative. Thankfully, after years of trial and error, they’ve now settled on an incredibly efficient process that consistently recruits the top talent on the planet.

Let’s dive in and explore this process by first highlighting the top four ways in which Google consistently finds and attracts superstars. Then, in Step 4, we’ll outline their innovative methods for interviewing, screening, and selecting the best.

Aided Recall

In the early years, as mentioned, Google almost exclusively relied on referrals for filling open roles. Personal recommendations were simply the best way to generate quality leads. Thus, after experiencing the aforementioned challenges with job portals, they decided to go back and find new ways to garner more referrals.

Eventually, they adopted a technique called “aided recall,” which is often used in the marketing world to test audience’s memory retention of advertisements. In that industry, subjects are first asked if they remember seeing a particular advertisement. Then, with the help of a verbal or visual aid, they are asked again. With this small nudge, the respondents’ recollection almost always improves.

Similarly, Google started using this method to jog the memory of their employees about people in their network that may be great referrals. Laszlo Bock describes it this way: “People tend to have a few people who are top of mind. But they rarely do an exhaustive review of all the people they know, nor do they have perfect knowledge of all the open jobs available. We increased the volume of referrals by more than one-third by jogging people’s memories just as marketers do. For example, we asked Googlers whom they would recommend for specifics roles: ‘Who is the best finance person you ever work with?’ ‘Who is the best developer in the Ruby programming language.’…Breaking down a huge question (‘Do you know anyone we should hire?’) into lots of small, manageable ones (‘Do you know anyone who would be a good salesperson in New York?’) garners us more, higher-quality referrals.”

Another way Google uses this technique is by initiating what they call “Sourcing Jams,” in which groups of twenty or thirty people get together for several hours and methodically go through all of their LinkedIn, Facebook, Twitter, Instagram and Google+ contacts, identifying anyone that may be an excellent referral. Once a potential candidate is identified, recruiters who are on standby immediately reach out to them and begin a relationship.

These two tactics have produced more than 100,000 employee referrals in a single year.

Map, Pursue, Cultivate

In addition to aided recall, Google also uses a tool called market mapping. It works like this: First, working closely with senior leaders, the People Operations team gets a solid understanding of where the company is headed strategically. Then, armed with this information, they outline current talent gaps and those that they may have in the future. Next, they go into the market and systematically locate and “map” every person within a universe of job types, companies, and industries that meet what they’re looking for.

Once a comprehensive list is generated, recruiters review portions of it with other Googlers who have expertise in that area or may know those individuals. They then check online to see if there’s anything else that could help identify those who would be most successful at the organization. Finally, they reach out and begin building a relationship.

Once contact is made, the hard work of cultivation begins. Patience is key. Sometimes it takes many years to finally recruit a best-in-class candidate. In fact, many of Google’s finest employees joined the organization only after they had been pursued for more than 10 consecutive years.

Engage Inbounds

As Google’s global awareness and success skyrocketed, so too did the number of quality applicants that came through their career site. In fact, their explosive growth drastically mitigated the amount of poor inbound leads they had experienced earlier with job portals.

Yet, unlike most career sites that are outdated, uninspiring, and have little utility, Google invested millions into building one of the most robust, engaging, and effective career sites in the world. Instead of just posting job descriptions online and waiting for a flood of applicants, Google encourages candidates to invite Googlers to their Google+ “circles” so that current employees can get a more holistic understanding (via photos, skill profiles, previous posts, and other personal content) of who they are, what they do best, and what they’re most passionate about. It’s not uncommon for applicants to chat directly with employees over Google Video as a first point of contact. They’re encouraged to ask questions about the company culture, the role, and the team.

Also, if a candidate isn’t selected for the position to which he/she applied, recruiters now have an easy way to cultivate relationships and reach out later when more suitable opportunities arise.

Hire Teams

When the referral pipeline runs dry, the pursue and cultivate process isn’t as expeditious as needed, and/or the career site isn’t generating a sufficient volume of quality inbound leads, the best option may be to recruit entire teams of people at a time. Although this sounds extraordinarily expense, it doesn’t have to be. In fact, sometimes this can be the least expensive solution.

For example, several years ago Google knew about a team in Denmark that had revolutionized the speed at which Web browsers ran. They had sold their company and were now exploring future opportunities. Microsoft reached out to them and offered everyone jobs, so long as they relocated to Redmond, WA. Google got wind of this and instead offered them an opportunity to stay in their hometown, thereby opening the first Google office in Denmark. They accepted and in the end, this investment paid off handsomely. The team went on to build the JavaScript in Chrome.

Aided Recall. Map, Pursue, Cultivate. Engage Inbounds. Hire Teams. These are the top four ways in which Google sources the top talent in the world. But how, then, do they interview, screen, and select the crème de la crème? What’s their process? Find out in the article Google’s Guide to Assessing and Selecting the Word’s Top Talent