As the adage goes: “You can pick your friends, but you can’t pick how many”. Well, doesn’t sound quite right, but turns out it’s very true. It’s not your fault though, it’s just Dunbar’s Number.

How many acquaintances can you handle? 150, give or take. The number is the result of a 1992 study by sociologist Robin Dunbar, and has heavyweight scientific backing. But functionally, what does it represent? I’ll let Wikipedia* explain.

The History Of Dunbar’s Number

Dunbar’s Number is a suggested cognitive limit to the number of people with whom one can maintain stable social relationships – relationships in which an individual knows who each person is and how each person relates to every other person.

Clear as day, right? Here’s an example: You know John, Mary, and Sally. You know how you interact with each of them; how you relate. You also know how John relates to Mary, Sally, and yourself. How Mary relates to everyone and so forth. Knowing how everyone connects and their relationships, Dunbar postulates that your group is socially stable. That cognizance runs thin as the group approaches 150 people and the resulting stability suffers. People stop understanding motivations, find it difficult to be empathetic, and so forth.

Before we get too deep, know that 150 is the commonly accepted representation**, not a hard and fast limit. Your brain doesn’t aggressively reject people at 151. While you may never understand who your parents really are, you don’t meet a random guy at age 28, hit your limit, and suddenly think you’re orphaned. However, on an operational level, there is historical context that backs up the general number.

Neolithic farming communities were known to be around 150 people before splitting into separate communities. Lower-level Roman military units were approximately 150 soldiers in size. Subsequently, modern units are typically categorized at 120 – 180.The average parish size for the Hutterites and Amish is consistent with Dunbar as well; denominations known for espousing communal living.

The value tends to repeat in social structures that heavily rely on interoperability of its members. Perhaps the most cited modern example is Gore-Tex’s parent company: W. L. Gore & Associates. Through trial-and-error, founder Bill Gore decided 150 employees per location was most ideal. The company went so far as to open locations with only 150 parking spaces. When those spaces were full, another location was constructed. Before his death in 1986, Bill explained about the practice: “We found again and again that things get clumsy at a hundred and fifty.” ***

What Does Dunbar’s Number Have To Do With Healthcare?

As fascinating as this is, you didn’t wander onto a sociology blog. I see Dunbar’s Number as having considerable health care implications. One of which has to do with the new organizational landscape. ACO’s, CIN’s, and Conveners need to all be aware of the functional limitations of an organization that grows to epic levels. Consider an ACO that contracts four-figures worth of providers across multiple states; how is that effectively managed at a local level? The overall Roman military was likely larger than 150; Gore has over 6600 employees. It makes sense to Dunbar that they both promoted strong organizational boundaries, while keeping a central authority. It might not serve as a perfect road map, but the structure pulls in an interesting direction that has a track record ACO’s shouldn’t ignore.

The idea becomes more urgent at a smaller scale; not necessarily, but potentially as a locality of the above example. Let’s say that you’re one of 10-15 providers who have grouped together for contractual leverage. Your social relationship with those 10-15 other providers is magnified, but easily managed. The relationship between the staff at each office is a different story.

Presumably, the provider’s distinct staffs will have some level of contact, even if at the administrative level. How do you make sure that the lines of communication stay strong and healthy? Do you cap some functional level of organization at a magic number? Do you limit the interaction to specific members of your office? Good to have these questions a little thought out and something close to an answer beforehand.

Communication Is Key

In either scenario, no matter the numbers, the key to everything good is communication (and comfortable shoes). You need to have a clear understanding of what is working and what is not. Who is performing and who could use improvement. How people are relating to what is needed of them. You need to have an easy way to convey your message, allow people to convey theirs, and just maybe get some actionable data back from the whole experience. There’s something to be said for a Provider Relationship Management offering that can do that and more.

Dunbar’s Number is a Unicorn for me. It crosses math with sociology at a level most everyone has experienced. It’s the rare thing on which we can all reflect and relate. Well, at least about 150 of us.

* – Dunbar’s Number – Say what you will about Wikipedia, but I like my sources like I like my commendations; cited.

** – Dunbar predicted a human “mean group size” of 148 (casually rounded to 150), a result he considered exploratory due to the large error measure (a 95% confidence interval of 100 to 230).

*** – Interesting point that reaching 150 was the result of deductive evolution by Gore. Dunbar’s study wasn’t published until 1992, 6 years after Gore had passed. Even more interesting is that Gore’s company can boast being a 20-year member of Fortune 100 Best Companies to Work For list. Counting as a member from inception in 1997 until just this last year. They’re doing something right.