One of the ways Scrum helps bring team members together is by mandating that teams remain small. Most of the Scrum literature recommends that teams consist of seven cross-functional members (plus or minus two). Certainly limiting the number of “communication channels” allows teams to engage in high-impact collaboration without too much scope to leave anyone in the dark. In fact, there is a relatively simple equation to illustrate how, as team members are added and communication channels increase, maintaining communication with the entire team becomes a considerable challenge.
The formula, in which “S” is equal to the number of communication channels and N represents the number of team members, can be represented as: S = (N (N-1)) / 2
Interestingly, as team members are added, the value of “S” (that is, the number of communication channels) increases dramatically. That is, if a team of six added two more developers to their team, the group size would increase to eight, but the total number of communication channels would increase from 15 to 28. Suddenly, the effort associated with communicating with all the other member teams has almost doubled.
Although it is recommended that Scrum teams be small, the framework protects against “groupthink”, that is, a passive herd mentality, by asking that teams be composed crosswise. In other words, Scrum teams should be created to represent a variety of job functions without much overlap. When traditional sequential development, better known as teams “cascaded” by function (testing, QA, etc.), Scrum prefers that all “phases” of development are present in a single cross-functional team. As such, a single Scrum team would likely include a mix of software engineers, architects, programmers, analysts, QA experts, testers, UI designers, etc. When people with different skill sets, areas of expertise, and development experience come together for the kind of collaboration that Scrum enables, it ensures that multiple perspectives are considered. In fact, when people with such diverse backgrounds brainstorm a problem, they may come up with a new solution as a group that they couldn’t have come up with independently.
On the other hand, imagine a team of 20 people trying to work together to solve a particularly difficult problem. Due to the large number of people, a leader, or a handful of them, is likely to emerge, and as a result, some team members may passively follow. Or something worse could happen: the size of the group could prevent you from making a fully considered decision, or any decision at all.