In my experience I found that there’s an ideal number of people that compose a team:
The perfect team size is the number of people that can sit around a table without breaking into multiple conversations.
This practical rule that I found and applied in my work was confirmed over time by other people that had the same experience, even if they sometimes phrased it differently, like “the number of people that can fit in a van”.
The table metaphor is useful because it shows clearly a situation that you’ve experienced, making it tangible. It also maps well to other characteristics:
- Focus — a table is a good metaphor for discussing and working together, face to face.
- Context — a table in a noisy environment will break in multiple discussions faster than a table in a perfectly silent space.
- Soft Skills — talking around a table also triggers all the good and the bad past experiences everyone had. Good turn taking and tone are the two most important soft skills probably here.
Due to these elements above, you’ll notice that the effective number to do teamwork is between 3 and 8, maybe 10 people, from the less ideal to the most ideal situation.
Recently I found some studies that tried to associate a specific number to this. While I prefer to use a metaphor for the reasons above, these analysis provide a good confirmation of the table rule:
Once you’ve got 7 people in a decision-making group, each additional member reduces decision effectiveness by 10%.
— M. Blenko, M. Mankins, P. Rogers (2010) Decide & Deliver (Bain & Company)
This resonates with me, and is a predictor of positive “group dynamic” as well. I coach executives, both individually and in groups. Groups smaller than 6 seem to lack the breadth of ideas and collaboration. On the other hand, groups larger than 8 become unwieldy, and there is not enough time or focus for each individual to contribute effectively.
— K. Purmal (2014) Decision Making and the Rule of 7
Groups containing 3 to 8 members were significantly more productive and more developmentally advanced than groups with 9 members or more.
Work-group size is a crucial factor in increasing or decreasing both group development and productivity.
— S. Wheelan (2009) Group Size, Group Development, and Group Productivity
A size around seven isn’t just interesting because more people will communicate with less efficiency and find an harder time to coordinate, but also because a smaller number of people will make every person critically important, and you get more resiliency with a few more people.
You might think that technology helps in increasing the number here. It’s true, but just to a certain extent. I’d compare a good technology to a silent room: you communicate better, but still there’s a limit beyond which the conversation will split.
And that limit is again the table rule, or slightly above that.
This doesn’t mean of course that you can’t discuss with more people, like on a blog, forum or activity stream. It just means that in terms of synchronous communication (i.e. chat) more than about 10 people talking exactly at the same time the chat becomes difficult to follow.
For a more in-depth review of communication tools for remote teams, you can check the three speeds model of collaboration.
Design An Effective Group Structure
When you need to create a good team organization for a company or a project it’s useful to keep in mind these two rules:
- The table rule — 3-8 people per team, depending on context and scope.
- Conway’s Law — the team structure and interactions have to match the structure of the product being built.
These are two simple and basic rules that help in defining the boundaries and relationship between teams, independently from any hierarchical or flat structure model.