Throughout the summer, we often include interns in our projects. Sometimes a new team member joins a team or as a project evolves, another person needs to jump on board. While it may seem like you are only adding one more communication path because there is one more person, it is actually a bit more complicated than that.

When one more person joins the project team, there is now one more individual to communicate with each existing team member, whether through a face-to-face conversation, email, Slack or Teams, or meetings.

This means one new person = multiple new communication paths. For example:

To determine how many more communication paths there are now so you can update your communication plan could be extremely complicated if you had to write it out this way every time, but thankfully there is a formula that we can use:

Communication Paths = N * (N-1)/2 Where N = team size

This simple formula has been tested and used for decades, and it makes planning communication much easier.

This is what the numbers end up looking like:

Participants	Channels
2	1
3	3
4	6
5	10
10	45
11	55
12	66
13	78
14	91
15	105
20	190
25	300

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Why this matters to Project Managers

The larger the team, the more communication paths exist, and the faster they multiply when someone new joins. That can feel overwhelming, but a clear communication plan helps reduce stress and increase efficiency.

Understanding how adding one person to the team affects communication helps the project manager know the most effective way of communicating with the team:

• A weekly all hands meeting
• Delegating communication through team leads
• Using structured updates
• Utilizing tools like Slack channels or shared documents

No matter the method, the goal is the same; information should not get lost.

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Tools that help manage communication complexity

This complexity is why many teams use tools like:

• RACI matrices
• Meeting matrices
• Stakeholder communication plans
• Information dashboards

These tools help clarify who needs what information, when they need it, and how it will be delivered.

Communication clarity is essential and planning for growth helps ensure that clarity doesn’t disappear.