This is a pretty nice insight:
Then, at some magical Dunbar number, you pass two interrelated inflection points. First, the number of new hires arriving exceeds your population’s ability to organically infect culture and values. Second, because of the vast swath of preexisting people, the arriving individual erroneously believes that they as a single person can no longer influence the cultural course of the company.
I tend to disagree with those causes and arguments.
First of all, Dunbar’s number is about size (~150 people) and not growth rate. I tend to question the degree to which it’s a hard-and-fast law. I’m skeptical of magic numbers, and there are so many other factors that influence culture. For example, when resources are abundant, it’s not hard to have a great culture. Scarcity is when the real test occurs (and 90+ percent of organizations fail). When people start not getting things they want, is the organization capable of handling it in a civilized manner? Resource scarcity is going to break a corporate culture much faster than passing some magic number of people.
Rapid growth hurts a culture, but I don’t think it’s fair to blame it on “the new people”. That assumes that the people inside the company were culturally superior to the “outsiders” and that’s often wrong. This isn’t Lake Wobegon: most corporate cultures are average and some are below average. The reason why rapid growth damages a culture is that (a) people stop thinking about automation because they can just delegate grunt work, and (b) people start angling to build their own empires. When you have rapid growth, people don’t care about technical debt pile-up because all the undesirable work is going to get dropped on someone else– someone who likely isn’t in the building yet.
In other words, the cultural problems that you get with rapid growth are as much a problem with the existing people as with “the new people”.
Second, because of the vast swath of preexisting people, the arriving individual erroneously believes that they as a single person can no longer influence the cultural course of the company.
… and now I’m going to sort-of contradict what I just said. One of the things that the VC-backed startups do that is often toxic is that they mislead new hires about their ability to influence the culture. These startups want everyone on the team to think he or she is its real leader, because people work a lot harder when they think that they’re in charge. Who would work a 14-hour day if he didn’t believe he was on a fast-track to be a major player? No one. Of course, this causes problems down the road when people learn that they’re actually not in charge. I point this out because I think that, in general, people tend to be led (intentionally) to overestimate their ability to change a company’s culture.
Why is the first true? Dunbar number doesn’t mean you are hiring lots of new people, it’s more about how large an organization is before you cannot know everyone, more or less. You can still hire at 1 person per quarter.