Dunbar’s number and the size of organizations

I am reading The Tipping Point at the moment. The book discusses the size of groups that are cohesive. Research has shown there is an upper limit to the size of such groups. This limit is 150 and is called Dunbar’s number. It has been proved in many different settings. Some research shows the major difference between humans and other animals is the size of groups that we can be part of.

Further research has shown that group size of around 150 works only in situations where people have a strong reason to stick together, such as armies or tribes facing a struggle for survival. When we are able to choose self we maintain a far smaller set around 50 or so.

This brings me to an observation in my own company. When I joined Mirabeau employed about 80 staff. It was well possible for most employees to know over 75% of their co-workers. As we grew gradually to over 160 we are now, I noticed that people actually know less people in absolute terms. When faced with a larger group People tend to stick with smaller groups they know.

I am pretty sure Dunbar’s number and the theory behind it, explains the rise and fall of many (online) communities. As communities become more popular they grow up to the point where communities fall apart. If you Google there is also some material on this phenomenon in online gaming.

Many fast growing companies use this theory to their advantage and use a cell based growth model. About 10 years ago this model was applied by two companies in the IT industry, CMG and BSO. When a unit approached 80 staff they would split the unit in two smaller units, to let them grow again.

I am still wondering how this works out for the 300+ connections I have on LinkedIn.

Further interesting reading on the Dunbar number.


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