I’ve written this same basic argument for small teams three or four times now, so to comply with the Don’t Repeat Yourself (DRY) principle I though I’d post it. In short, this argument repeats Brooks’ Mythical Man-Month concept 🙂 , and asserts that you must restructure the communications dynamics of a team when it changes in size, regardless of whether or not your project is late.
To paraphrase one of the points made in Frederick Brooks’ The Mythical Man Month, complexity in a system scales with the number of interfaces. Applied to a team communications system of N people, the worst-case number of total communications channels is when everybody talks to everybody else. This can be expressed by N(N-1)/2. In other words, a given person in the team (the Nth person) is communicating with everyone else (N-1 people).
A problem with large horizontal teams is that as N increases, the communications overhead of being able to operate potentially increases exponentially. As a member of a 5 person team, for example, communicating with 4 others is not a big deal. You are able to mentally understand what other people are doing and how others communicate with each other (in all 10 different relationships). If this team grows to 15 people, however, communicating is not as simple. In the worst case, not only do you have to communicate with 14 other peers, there are now 105 relationships between people you may have to be aware of to stay “in the loop”. The worst part may be that the majority of the information going across those channels may be directly irrelevant to you job, but since itâ€™s relevant to the team as a whole, you spend the time and mental cycles to process it.
Now, this is all worst-case abstract theory, but it does highlight the scaling problems of communication in teams of changing size. As your team changes, you need to reevaluate the way it works to keep operating overhead due to excess or insufficient communication down to a minimum.