I’ve always loved the power of this visual from Lighthouse, representing Brooks Law and the number of lines of communication that exist in a team of a given size. It really demonstrates the mounting challenge of keeping people on track and in sync as team size grows:
Large team size presents significant overhead in terms of comms between the members of the team. The Scrum Guide has standardised on 6 +/- 3 as the best team size - so, between 3 and 9 people, PLUS the Scrum Master and Product Owner.
I can never remember the formula to calculate the number of relationships, despite it being quite simple - n*(n-1)/2 - so I put together this super-simple SIRI shortcut to help me out.
So…when you need to put the case forward for smaller team sizes this handy Siri shortcut can quickly prove a point. Simply enter the number of development team members and it spits out the number of lines of communication between the team members. Enjoy!