150 is the most important number in business that you didn’t know about.

At face value, this number is rather inconspicuous as it’s the sum of eight consecutive primes [7 + 11 + 13 + 17 + 19 + 23 + 29 + 31]. Interesting indeed, but you’re probably wondering, “OK, thanks Instill for the elementary school math lesson…but what’s the point?!”

It turns out that the number 150 has a lot of significance well beyond elementary school mathematics. 150 is the size a human group can grow to before connections and relationships start to fray. It’s why, at least in our opinion, 150 is the most important number in business. And it’s a number that can help us make sense of the many challenges organizations face as they grow.

What is Dunbar’s #?

In the 1990s, an anthropologist by the name of Robin Dunbar studied groups of primates and their social structures. He found that the volume of a primate’s neocortex — the outermost layer of the brain — correlated with the numbers of individuals in their respective social groups. Accounting for human neocortex volume, Dunbar predicted that the human brain would comfortably handle 150 stable relationships. And, after 150? He found that communication starts to break down and that close relationships become harder to maintain.

Basically, our brains don’t have the size or compute power to keep track of everyone in the group.

The Tipping Point

Founders and CEOs of small companies can easily interact with every employee — the close proximity, flat reporting structure, and free flowing communication facilitate the shared sense of community. However, companies often find that once they surpass 150 employees, strange inefficiencies develop and workers lose sight of goals. This change requires companies to invest in structural needs for communications, decision-making, and culture management.

A likely reason for this breaking point is Dunbar’s number. The dynamics change for any group when it grows beyond 150 people. Companies are no different. As organizations grow, there is no playbook to ensure that cultural values grow with the organization.

The dynamics change for any group when it grows beyond 150 people. Companies are no different.

Here’s Robin Dunbar’s insight on organizational change:

“There is no question that the dynamics of organizations change once they exceed about 150 or so. The Hutterites deliberately split their communities at this size in order to avoid having to have both hierarchies and a police force. Keeping things below 150 means you can manage the system by peer pressure, whereas above 150 you need some kind of top down, discipline-based management system.”

Managing Culture Growth beyond 150

At Instill, we believe that you simply cannot manage what is not measured. Unfortunately, organizations have operated in the dark with inadequate tools for too long. It’s why we’re building a tool set for active culture management. Our culture operating system is a single place to get a continuous pulse of your organization’s cultural health.

Developing a data-driven approach around culture, such as propensity of innovation and measurements of productivity can amplify the employee experience. And bridging this connection between organization and employee can increase the sense of purpose and belonging.

Companies that can communicate their values and foster an ongoing connection in our new world of remote / hybrid work can prove that Dunbar’s limit of 150 is not a limit to their long-term success.

Do you have thoughts or questions about company culture?

We would love to hear from you. Chat us at www.instill.ai to find out more.

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