When to use it
Use it to explain why informal coordination becomes harder as a group grows.
Check before calculating
It is not a forecast of message volume, meeting time or actual working relationships.
- Define the scope, status date and units before collecting the inputs.
- Substitute the values into the formula and retain their units.
- Interpret the result against the assumptions and decide what evidence or action is needed next.
Formula & inputs
Channels = n × (n − 1) ÷ 2
n is a whole-number count of people. Each pair is counted once.
Worked example
A delivery group contains eight people. Any member could communicate directly with any other member.
8 × (8 − 1) ÷ 2 = 28
There are this many possible pairs, not necessarily this many communication needs. Design the important routes around decisions.
Common pitfall
Using the count as a staffing limit ignores structure, tools and the nature of the work.
Source & related material
Standard quantitative technique; this explanation is by fannarmaximus. No single inventor is claimed. The arithmetic is computed from explicit inputs, not copied from an official sample question.