Is there an ideal size for teams and organizations?

Lately I’ve been reading a lot about “Dunbar’s number,” which is based on research by British anthropologist Robin Dunbar who claims that the optimal size of communities, and even business organizations, is approximately 150 members. If you push the boundary on that, relationships among group members tend to break down.

This is why, for instance, manufacturer W.L. Gore—famous for its non-hierarchical, team-based management structure—builds a new branch every time one branch exceeds 150. Within this limit each member has the cognitive capacity—specifically the brain size—to process the complex data necessary to maintain stable relationships with everyone else.

More interesting to me, however, are the smaller numbers that Dunbar assigns to more intimate groups: three to five for our closest friends and 12 to 15 for the next level of intimacy. Coincidentally, many work groups and committees I’ve coached are approximately 12 to 15, and they often divide up into sub-teams of three to five in order to tackle short-term tasks.

But wait (don’t touch that dial)—there’s more! The same numbers seem to hold up for rock bands. The majority of bands are 3 to 5 members (with the occasional 6- or 7-person group) while the extended team—including sound engineer, roadies, business manager, booking agent, etc.—often stretches to about a dozen.

Dunbar has plenty of critics who reject his “reductionism” (and I have some skepticism myself) but his numbers are fun to noodle on. And it gives me an excuse to not keep up with all my Friends on Facebook: I just don't have the brain size.

For further reading on Dunbar's number, look here.

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  1. Interesting. I don't buy it in today's world. You have Apple with 50,000 employees or whatever, and then other individuals with tons of power, prestige or $ that can get things done.

    As for bands...I always liked 4...Beatles, Who, Kiss, Led Zep, the Who.

    Facebook sucks.

  2. "I have some skepticism myself"

    So, how come you left out the best part? Tell us about your skepticism, 'cause I see Dunbar's validity all over the place. But then, you see stuff I don't, 'cause you're facing east, or something like that.

    Also, because these days, I tend to be in a group of 2 most of the time, unless you truly believe that married folk are "one flesh" which would make Best Beloved and I a group of one.

  3. David, Dunbar accounts for larger groups, according to the BusinessWeek article: "Beyond 150 there are further rings: Fifteen hundred, for example, is the average tribe size in hunter-gatherer societies, the number of people who speak the same language or dialect. These numbers, which Dunbar has teased out of surveys and ethnographies, grow by a factor of roughly three."

  4. Joel, two data points give me pause…

    1. I notice a lot of small companies — and departments within larger companies — populated by 20 to 30 people.

    2. According to a Harvard Business School working paper, “From the mid-1980s to the mid-2000s, the size of the executive team (defined as the number of positions reporting directly to the CEO) doubled from 5 to 10 positions.”

    On the other hand, according to the BoardSource 2010 Governance Index Survey, the median size of a Board of Directors is 15 — which is within Dunbar’s parameters.

  5. The problem with bands when they go beyond 4 or 5 members is that the royalty split is so small you end up working for even less than peanuts. Plus the van is a truly awful place to be on those long drives.

    I suspect there's a correlation between 3 - 5 intimate friends and 3 - 5 core team members with the fact that if you've got more than 3 - 5 key tasks, nothing gets done as well as it should. For all the talk about multi-tasking, seeing the bigger picture and so forth, we seem to do better when we break big jobs down into small parts and focus on getting a small number of things done well. "That's one small step..."

  6. Mark, I spent a LOT of overnights in Econoline vans in my distant past. One of my bands (over forty years ago) had a converted school bus with bunk beds. We drove it from NYC to San Francisco to LA one summer. We'd play a gig then sleep in the bus. For some reason the good folks of Beverly Hills and West Hollywood didn't take well to a bunch of long-haired freaks piling out of a school bus in their neighborhood. They didn't seem to understand the economic contribution we were making to the area.

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