Mission is what motivates employees.

And yet every day my co-founders came to work early and stayed late. We were on a quest to augment search, data analytics, and network connectivity with real identity, reputation, and trust. The goal: Building a platform that creates economic opportunity for every member of the global workforce. It was an ambitious vision and it gave us a great sense of purpose.

In a start-up environment, when teams are small and most everyone who's involved is, by nature, a risk-taker with a desire to create something that will potentially have outsized impact, it's relatively easy to find purpose-driven individuals.

But to become the company we wanted to become, we knew that we'd eventually need more employees, with different skillsets and different temperaments. And inevitably our culture would change. As I and my fellow instructors explain in our Blitzscaling class at Stanford, a company with 100 employees cannot function effectively using the tactics that work for a company with 10 employees: You need an updated playbook.

Still, my co-founders and I were determined to preserve our shared sense of purpose as a core value, even as we grew. In job interviews, and then again, in new hire orientations, we always emphasized our guiding value: Individual LinkedIn members always come first. Any addition or change we make to the platform must improve it in ways that help individual members increase their economic opportunities.

In emphasizing our philosophy so persistently, we inevitably dissuaded some talented potential hires for whom it did not resonate. But we also attracted individuals who did connect with it, and thus ensured our ongoing cohesiveness even as we started to expand beyond our core team.

Today, LinkedIn has more than 9200 employees. Needless to say, we've moved out of my living room, into offices in more than 30 cities around the world. Our selection of complimentary beverages has scaled up rapidly.

But while the Wild Alaskan Salmon with Avocado-Corn Relish in our café and our 401K matching program make it nicer to work here, a strong sense of purpose remains the defining attribute of our employees.

In fact, a consultancy called Imperative that publishes a national index measuring how purpose-oriented the U.S. workforce is across industries, job types, and more, recently surveyed 2000 of LinkedIn's global employees. It found that 41 percent of them fit its purpose-oriented profile – they prioritize meaning and fulfillment over money and status. That's nearly twice as high as the U.S. tech industry average of 21 percent.

LinkedIn benefits from this orientation in a number of ways. According to Imperative's research, purpose-oriented employees are:

* 54 percent more likely to stay at a company for 5-plus years* 30 percent more likely to be high performers* 69 percent more likely to be Promoters on Bain & Company's eNPS scale, which measures employee engagement and loyalty

In The Alliance, my co-authors and I present the "tour of duty" as a mechanism for creating and maintaining engagement in an era when lifetime employment is no longer a given. The key to a successful tour of duty is a high degree of alignment between employer and employee. And the key to a high degree of alignment is a shared sense of purpose.

When that shared sense of purpose exists, employees stay at a company longer. Their high level of engagement leads to higher levels of loyalty and performance.

In the old days of lifetime employment, the presumed payoffs were security and predictability. Now, more and more professionals look for positions at companies where they can create meaningful impact and experience personal growth.

Companies that understand the increasing emphasis of purpose in today's professional landscape improve their ability to attract such employees and also their ability to retain them for longer periods of time.

And of course a virtuous loop inevitably kicks in. At LinkedIn, when I see how thousands of LinkedIn employees are committed to creating economic opportunity for every member of the global workforce, I get even more inspired about where we're headed. Jeff Weiner calls this shared sense of vision LinkedIn's true north. It has guided my own efforts for more than a decade now, and it continues to help us attract and retain exactly the kind of committed professionals who are helping us realize our vision.